Environmental impacts of Broiler chicken production in the North Eastern Himalayan region of India: Evaluation using the Life Cycle Assessment approach

22 The work was supported by the ICAR-Poultry Seed Project, ICAR Research Complex for NEH 23 Region, Nagaland Centre, Medziphema-797106, India (PIMS Code: OXX01915). The authors 24 sincerely acknowledge the cooperation and support of the broiler farms, which generously 25 provided the primary data for the study. Also, the authors acknowledge the support of The 26 Energy and Resources Institute, Delhi, for collaborating in this study. 27 28 .CC-BY 4.0 International licenseavailable under a (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made The copyright holder for this preprintthis version posted March 18, 2026. ; https://doi.org/10.64898/2026.03.16.712132doi: bioRxiv preprint 2

29 The study presents the first comprehensive environmental assessment of broiler chicken 30 production in India, from a cradle-to-farm-gate perspective, using the Life Cycle Assessment 31 (LCA) approach. The objective of the study was to identify environmental hotspots in the broiler 32 production system. All inflows and outflows of the broiler production system were mapped to 33 construct the life-cycle inventory. This study uses a system boundary that extends from the 34 cradle to the farm gate. Inventory data for the broiler chicken farms were collected from six 35 different farms, which is typical of the Indian broiler production system, and background data 36 were sourced from the Ecoinvent 3.0 database. For the LCA study, SimaPro (v 9.3.0.3) was used 37 with the ReCiPe 2016 Midpoint impact assessment methodology. For this study, the functional 38 unit of the “1-kg live weight chicken produced was taken into consideration”. The environmental 39 impact categories assessed were mainly Global Warming Potential in hundred years (GWP), 40 stratospheric ozone depletion, freshwater eutrophication, terrestrial ecotoxicity, land use, etc. 41

showed that broiler chicken feed was primarily responsible for environmental impacts, 42 followed by transportation and electricity. Broiler chicken production had a total GWP of 3.77 43 kg CO2-eq per kilogram of live weight. Specifically, the energy component of feed, viz., maize 44 production, was the main source of environmental impact. The process of transporting feed and 45 chicks to the broiler farm also had a significant environmental impact. The broiler production 46 system was found to have moderate environmental impacts compared to other published LCA 47 studies of chicken production. Based on the findings of the present study, we proposed 48 actionable items to further improve the environmental efficiency of broiler chicken production in 49 India. 50

Broiler meat production, Environmental impact, Greenhouse gas, Life Cycle 51 Assessment, India. 52 53 54 55 1. Introduction 56 .CC-BY 4.0 International licenseavailable under a (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made The copyright holder for this preprintthis version posted March 18, 2026. ; https://doi.org/10.64898/2026.03.16.712132doi: bioRxiv preprint 3 In the years ahead, demand for livestock products is expected to rise dramatically due to 57 rising wealth, urbanization, and a projected global population of 9.6 billion by 2050. The 58 livestock sector is crucial to sustainable food security and health. Globally, poultry meat is the 59 most consumed meat (OECD-FAO, 2020). To keep up with rising demand, global poultry meat 60 production rose dramatically from 9 to 133 million tonnes between 1961 and 2020. In 2020, 61 chicken meat share was 40 percent of total world meat production, with much of the growth 62 observed in Asia, where production has increased almost fourfold (FAOSTAT, 2022). 63 India is one of the world's largest producers of eggs and broiler meat. The poultry sector 64 is the fastest-growing agri-sector in India and contributes one percent to the national GDP. 65 Poultry meat accounts for 50 percent of total meat production in India and ranks 5th globally 66 (Government of India, 2019). Chicken meat is widely accepted in India without any religious or 67 socio-cultural restrictions. The substantial growth in per capita income and the urban population, 68 particularly the middle class, has significantly driven demand growth (Singh et al., 2022). The 69 broiler industry has been growing at an average of 8-10 percent over the last 20 years and 70 currently accounts for around two-thirds of total poultry output. The industry has a high level of 71 vertical integration. Integrators supply the chicks to the broiler farm. The broiler farms rear the 72 chicks to slaughter weight. Adult birds are either purchased by a wholesaler or sold directly by 73 broiler farms. Approximately 90-95 percent of total sales volume is live birds, while cold storage 74 accounts for around 5 percent. 75 On the other hand, the increased chicken meat production contributes significantly to the 76 environmental impacts, including air, land, soil, water, and biodiversity (Costantini et al., 2021; 77 Ogino et al., 2021). There is a need to produce more with limited natural resources and with 78 fewer environmental impacts. Along with milk, poultry products are considered to have the least 79 environmental impact among animal-source foods, especially in terms of carbon footprint and 80 resource depletion. The land use and energy requirement per unit of chicken meat are low (de 81 Vries and de Boer, 2010; Roma et al., 2015). However, when compared with a broader basket of 82 edible fresh foods, these products fall into the medium-high impact category (Clune et al., 2017; 83 Duarte da Silva Lima et al., 2019). Also, there is increased consumer awareness of food with a 84 lower environmental impact. 85 .CC-BY 4.0 International licenseavailable under a (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made The copyright holder for this preprintthis version posted March 18, 2026. ; https://doi.org/10.64898/2026.03.16.712132doi: bioRxiv preprint 4 Life Cycle Assessment (LCA) involves the "compilation and evaluation of the inputs, 86 outputs and potential environmental impacts of a supply chain throughout its life cycle" (ISO 87 14040, 2006a). In essence, it considers all environmental consequences of resource use, land use, 88 and emissions associated with the product's processes. Using LCA enables us to assess the 89 environmental impact of products throughout their life cycles, from beginning to end. ISO 90 14040:2006a and 14044:2006b regulate and standardize LCA, which is founded on four main 91 components (goal and scope definition, inventory, impact assessment, and interpretation of 92 results). LCA is the most widely used methodology for quantifying the environmental impacts of 93 food products (Roy et al., 2009). LCA has long been used to evaluate the environmental impact 94 of food items. Furthermore, it is also a tool for making environmental management decisions 95 (Andersson et al., 1994; Costantini et al., 2021; Djekic and Tomasevic, 2016; Vázquez-Rowe et 96 al., 2012). Life Cycle Assessment of chicken meat production system has been reported from 97 USA (Leinonen et al., 2012; Pelletier et al., 2014; Putman et al., 2017), Canada (Pelletier, 2018), 98 Europe (Cesari et al., 2017; González-García et al., 2014; Tallentire et al., 2019), Australia 99 (Bengtsson and Seddon, 2013; Wiedemann et al., 2017) and Brazil (Duarte da Silva Lima et al., 100 2019; Prudêncio da Silva et al., 2014). Many LCA studies have been reported on the poultry 101 sector across different regions of North America and the USA, but few have been reported from 102 India. Despite the size and fast growth rate of the broiler industry in India, no reports are 103 available on the environmental efficiency of its production system using LCA. Hence, the 104 current investigation was undertaken with the following objectives: (i) to evaluate the 105 environmental impacts of the broiler production system in India from cradle to farm gate, using 106 the LCA, and (ii) to identify the hot-spots that contribute to environmental impacts in broiler 107 production systems. The findings of this study will be helpful to academics and policymakers in 108 India in addressing the critical environmental impacts of broiler production systems. 109 2. Materials and methods 110 The study was conducted in Nagaland and Assam, which are the North Eastern states of 111 India (Figure 1). Primary data were collected from six broiler farms representative of the broiler 112 production system in India. The description of the broiler farm and data modeling methodology 113 is described in the following sections. 114 2.1. The broiler production system of India 115 .CC-BY 4.0 International licenseavailable under a (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made The copyright holder for this preprintthis version posted March 18, 2026. ; https://doi.org/10.64898/2026.03.16.712132doi: bioRxiv preprint 5 The study site is located in a sub-tropical region (Figure 2) with a monsoon-type climate 116 (Agromet observatory, ICAR Nagaland Centre). In summer, the climate is hot and humid, and in 117 winter it is pleasant and cold. The annual precipitation was 1563.1 mm (mostly from June to 118 September). 119 The present study analyzed the intensive broiler production system (Figure 3), and for 120 this, primary data (Table 1 and Table 2) were collected from six broiler farms located in 121 Dimapur district of Nagaland (latitude: 25°54′ N, Longitude: 93°44′ E) and Karbi Anglong district 122 of Assam (latitude: 26.18°N, Longitude:93.58°E ). In brief, the broiler production system in 123 India is vertically integrated, with integrators or poultry firms supplying day-old chicks, feed, 124 and medicine to small- to medium-sized contract broiler production farms. After 25 to 42 days, 125 the integrators purchase back the live adult chicken for processing or sale to wholesalers. 126 However, the farmers also raise the broiler chicken independently and sell them to wholesalers 127 or retailers. 128 The study was based on primary data collected from six commercial deep-litter broiler 129 farms, each monitored over six consecutive production cycles within one year (36 cycles in 130 total). All farms were using similar housing design, broiler genetics, veterinary protocols, and 131 feed formulations. These farms are typical of intensive commercial broiler production systems 132 that dominate organized poultry production in India and NEH India and are thus considered 133 representative of modern, integrator-based broiler production in India. We do not aim to 134 represent backyard or smallholder systems, but rather the industrial segment that supplies the 135 majority of formal market broiler meat in the country. 136 2.2. Life Cycle Assessment methodology 137 LCA is a holistic tool for analyzing the environmental efficiency of a product and 138 includes the environmental impacts of all resources used throughout the product's life cycle, 139 from cradle to grave (ISO 14040, 2006a; 14044, 2006b; LEAP, 2016). FAO (2016) introduced a 140 harmonized international approach to analyze the environmental performance of poultry supply 141 chains across a wide range of production systems. This study followed the attributional LCA 142 (Alca) approach, i.e., the environmental impacts of the physical inputs and the output flow of the 143 system were assessed. The LCA procedure consists of four phases: (1) goal and scope definition, 144 (2) life cycle inventory analysis (LCI), (3) life cycle impact assessment (LCIA), and (4) life 145 .CC-BY 4.0 International licenseavailable under a (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made The copyright holder for this preprintthis version posted March 18, 2026. ; https://doi.org/10.64898/2026.03.16.712132doi: bioRxiv preprint 6 cycle interpretation (Figure 4) (ISO 14040:2006a and 14044:2006b). As per the specification, the 146 broiler production system in the present study is mapped for one year. 147 2.2.1. Goal and scope definition 148 The scope of this study was to analyze the environmental impacts of broiler production 149 systems from day-old chicks to slaughter age (42 days), with a particular focus on quantifying 150 GHG emissions and other impact categories. The time limit of the primary inventory was from 151 day-old chicks to broilers for slaughter (cradle-to-gate studies, ISO 2006a, 2006b). 152 2.2.1.1. System boundary and functional unit 153 The system boundaries included in the LCA assessment are depicted in Figure 5. The 154 system boundary started from the transportation of day-old chicks to the broiler production farm. 155 The transportation of chicks to the broiler farm is included in the system boundaries. The chicks 156 are raised in a poultry bed made of paddy husk, which is also included in the system boundary. 157 During the 42-day fattening period, the chickens are fed with starter and finisher compounded 158 feed, mainly comprising maize, palm oil, soya meal, fish meal, limestone, and other ingredients 159 (Table 3). The life cycle inventory for each ingredient was modelled separately and aggregated 160 to obtain the environmental profile of 1 tonne of complete feed, which was then multiplied by 161 the feed intake per kg live weight in each farm cycle. The production and transportation of 162 chicken feed are included in the system boundaries. Throughout the growth phase of chickens, 163 water (for cleaning and drinking), elctricity and diesel were used and are included in the system 164 boundaries. The use of vaccines and antibiotics in raising broiler chickens was excluded from the 165 system boundaries due to insufficient information. Chemicals and detergents were used for 166 cleaning activities on the farm; however, they were not considered for assessment due to their 167 insignificant contribution to environmental impacts, as reported in previous studies (Castanheira 168 et al., 2010; González-García et al., 2014). In India, broiler production systems extend from the 169 cradle to the farm gate (live birds) with minimal slaughterhouse processing. As reported earlier 170 (Costantini et al., 2021), the production phase has the most significant impact on animal 171 products. According to ISO 14044:2006 b, the functional unit shall be consistent with the goal 172 and scope of the study, as well as with the system boundaries. The primary functional unit (FU) 173 was 1 kg live weight (LW) of broiler at the farm gate. In addition, a secondary nutritional 174 functional unit was used: 100 g of edible protein from broiler meat. This allows comparison of 175 environmental impacts per unit mass and per unit of nutritional value. 176 .CC-BY 4.0 International licenseavailable under a (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made The copyright holder for this preprintthis version posted March 18, 2026. ; https://doi.org/10.64898/2026.03.16.712132doi: bioRxiv preprint 7 Birds were reared on deep litter year-round. Litter and manure were not removed between 177 cycles, but accumulated on the floor and were removed once per year and applied to nearby 178 cropland as organic fertilizer. Nitrogen excretion was estimated from feed nitrogen intake minus 179 nitrogen retained in live weight gain, using standard retention coefficients for broilers. Volatile 180 solids (VS) excretion was estimated from feed digestibility assumptions. Methane and nitrous 181 oxide emissions from housing and storage were calculated following IPCC 2019 Refinement 182 Tier 1/2 guidance for poultry, using system-specific emission factors for deep litter. Direct N /i2 O 183 emissions were calculated as Nex × EF /i2 , and indirect N /i2 O as (NH /i2 + NOx volatilization) × 184 EF/i2 . The resulting CH /i2 and N /i2 O emissions were expressed as CO /i2 -equivalents using the 185 IPCC AR5 100-year GWP values. 186 Because all collected manure was applied to cropland, we used a substitution approach, 187 assuming that the nutrient content (N, P /i2 O/i2 , K/i2 O) of poultry manure replaced an equivalent 188 amount of synthetic mineral fertilizer. The avoided production and application of synthetic 189 fertilizers were credited as negative emissions in the system, providing a more complete 190 representation of the environmental consequences of the manure management strategy. 191 Cut-off criteria : The following cut-off criteria were selected as per the goal and scope of the 192 study: the production and maintenance of boiler farms (buildings) and equipment were not 193 included in the assessment. Similarly, cleaning products, disinfectants, pharmaceuticals, or chick 194 production (breeding and hatching) were excluded from the system boundary. Due to the 195 significant uncertainty associated with land-use change (LUC), this aspect was not included in 196 the study. 197 Allocation procedures: Allocation is the partitioning of the input or output flows of a process or a 198 product system between the product system under study and one or more other product systems 199 (ISO 14044:2006b). Allocation is used for multi-functional processes and can significantly affect 200 results. As per the literature (Duarte da Silva Lima et al., 2019; González-García et al., 2014), 201 product allocation was not applied in this study. In the broiler chicken production farm, the main 202 product is live chickens. Poultry manure is removed from the poultry farm at the end of a year of 203 production and used as fertilizer. This transaction represents a negligible fraction of the farm's 204 total output volume. The manure was considered as residual flow without allocation of impacts. 205 2.3. Life cycle inventory analysis (LCI) 206 .CC-BY 4.0 International licenseavailable under a (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made The copyright holder for this preprintthis version posted March 18, 2026. ; https://doi.org/10.64898/2026.03.16.712132doi: bioRxiv preprint 8 In life cycle assessment studies, it is important to have real, reliable data to obtain 207 representative, relevant results. For this study, life cycle inventory data were collected through 208 personal visits to six broiler chicken production farms in the Indian states of Nagaland and 209 Assam in 2022. The broiler chicken farms were comprehensively assessed and inventoried to 210 obtain representative data. Primary data, such as chicks raised per cycle, number of cycles per 211 year, mortality (%), average body weight (kg), total feed used, feed conversion ratio, diesel used 212 in a year, paddy husk used in a year, etc., were collected from the broiler production facilities. 213 For each farm–cycle combination, resource use was normalized per kg live weight and then 214 averaged across cycles and farms. 2.4. Life cycle impact assessment (LCIA) 215 The LCIA step involves calculating the environmental impacts of products or systems 216 based on inventory data. As per the international guidelines of LCA methodology (ISO 14040, 217 2006a), only classification and characterization were undertaken in this study. As per the scope 218 and goal of the study, normalization and weighting were not done. For this study, the impact 219 assessment methodology was based on Life Cycle Impact Assessment (LCAI) methods (ISO 220 14040, 2006a). The Sima Pro software (v 9.3.0.3) was used to analyze the data. The impact 221 assessment methods used were ReCiPe 2016 Midpoint (H) V1.03 / World (2010) H. The 222 midpoint characterization was selected because it has a stronger relationship with environmental 223 flows and relatively low uncertainty (Hauschild and Huijbregts, 2015). 224 The broiler production system utilizes resources and emits substances into the 225 environment, affecting air, land, and water quality. These emissions and resource usage are 226 categorized according to different environmental impact categories (ISO 14040, 2006a). The 227 impact categories used in the present study are listed in Table 4. These impact categories were 228 assessed for this study because (1) these are the most widely used and accepted categories in 229 environmental impact studies across the different livestock production systems and (2) 230 environmental impact from livestock production systems is related to these impact categories 231 (Prudêncio da Silva, 2014; LEAP, 2016; Wiedemann et al., 2017). 232 233 2.5. Life cycle interpretation 234 The explanation of the inventory phases, results, and impact categories was conducted in 235 accordance with the study’s goal and scope (FAO, 2016). 236 3. Results 237 .CC-BY 4.0 International licenseavailable under a (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made The copyright holder for this preprintthis version posted March 18, 2026. ; https://doi.org/10.64898/2026.03.16.712132doi: bioRxiv preprint 9 The GWP of the broiler production system was found to be 3.77 kg CO 2-eq per kg of 238 live weight broiler chicken produced (Table 5). The major contributors to the GWP (Figure 6) 239 were feed (2.1 kg CO2-eq per kg of live weight), followed by transportation (0.93 kg CO2-eq per 240 kg of live weight) and electricity consumption (0.60 kg CO 2-eq per kg of live weight). In 241 percentage, feed contributed 55.7% of GWP (Figure 6), followed by transportation (24.74%) and 242 electricity (15.91%). The impact of paddy husk and diesel usage on the GWP of broiler chicken 243 production was found to be insignificant. Terrestrial acidification was found to be contributed 244 primarily by feed, followed by transportation and electricity (Figure 7). However, transportation 245 (53%) contributed the maximum to terrestrial ecotoxicity, followed by feed (40.83%). In the case 246 of land use, 96% was contributed by feed. Feed and transportation accounted for 35.77% and 247 28.44% of fossil resource scarcity, while diesel and electricity accounted for 20.18% and 248 14.67%, respectively. 249 Broiler feed accounted for the greatest share of the environmental impacts of the Indian 250 broiler chicken production system. Therefore, a detailed impact analysis of the major feed 251 ingredients was conducted. Among the different feed ingredients (Table 6), maize was 252 responsible for 80% of the total GWP of the feed (1.68 kg CO 2-eq per kg of live weight), 253 followed by soybean meal (0.27 kg CO 2-eq per kg of live weight). In addition, maize was found 254 to contribute 87% and 79.48% of the total terrestrial ecotoxicity and fossil resource scarcity, 255 respectively. In the case of land use, soybean meal and maize accounted for 50.87% and 47.53% 256 of total land use by feed. Soybean meal production contributed 50% to the water consumption of 257 feed, while maize production contributed 22.5%. 258 4. Discussion 259 In India, the broiler chicken industry is consistently growing at an annual growth rate of 260 8-10 percent and is expected to expand further. It contributes significantly to the national GDP 261 and provides employment opportunities to millions of people. This industry is mainly growing 262 due to industrialization, an expanding economy, a growing middle class, and the emergence of 263 vertically integrated poultry companies that benefit from economies of scale. However, as the 264 poultry industry continues to grow, the impact on finite resources and impacts from production 265 processes will also increase. Therefore, it is crucial to maintain high efficiency throughout the 266 supply chain. Despite the industry’s significant contribution to the economy, no LCA study has 267 assessed the environmental impacts of the Indian broiler chicken production system. To the best 268 .CC-BY 4.0 International licenseavailable under a (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made The copyright holder for this preprintthis version posted March 18, 2026. ; https://doi.org/10.64898/2026.03.16.712132doi: bioRxiv preprint 10 of the authors’ knowledge, this is the first LCA study reporting the environmental impact of the 269 broiler chicken production system in India. 270 The production and use of broiler chicken feed are major contributors to environmental 271 impacts across all categories. Specifically, broiler feed production can be considered a hotspot 272 for the environmental impacts of broiler chicken production in India. These findings are 273 consistent with numerous previous studies (Bengtsson and Seddon, 2013; Castanheira et al., 274 2010; Costantini et al., 2021; Duarte da Silva Lima et al., 2019; González-García et al., 2014; 275 Ogino et al., 2021; Pelletier, 2008; Wiedemann et al., 2017). Feed production was examined in 276 detail to identify the main environmental hotspots of the broiler chicken production system in 277 India. Among the various components of broiler chicken feed, maize production contributed the 278 most across all categories, except land use and water consumption. Maize is a nutrient-279 exhaustive crop and requires large amounts of organic and inorganic fertilizers. Besides, it also 280 requires regular application of herbicides, weedicides, and insecticides. As maize accounted for 281 almost 60% of the feed, its contribution to overall environmental impacts was substantial. In line 282 with our findings, Wiedemann et al. (2017) reported that environmental impact was greatest 283 from wheat, followed by sorghum and soybean meal in Australian chicken meat production. 284 Conversely, some previous studies have identified the protein components (mainly soybean) of 285 the feed as the major contributors to environmental footprints (Ogino et al., 2021). This is 286 especially true for European chicken production systems, which heavily rely on imported 287 soybeans from South America, where land-use change is significant (Costantini et al., 2021; 288 Dekker et al., 2013). In the present study, soybeans' contribution to environmental impact was 289 significant in the land use and water consumption categories. This may be due to lower soybean 290 productivity and irrigation water use. Costantini et al. (2021) reported that protein feeds have the 291 greatest environmental impacts due to land-use change. In the present study, land-use change 292 was not considered due to insufficient information. Nevertheless, the global warming impact of 293 soybeans accounted for only 12.85% of the total feed impact in the current study. Therefore, 294 based on the findings of the present study, it is recommended to use locally produced grains in 295 broiler chicken feed, as the region produces sufficient quantities of maize and soybeans. The 296 production system for maize and soybeans in this region is a low-input, high-output system that 297 uses only rainwater and organic fertilizers, which may have lower environmental impacts. 298 .CC-BY 4.0 International licenseavailable under a (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made The copyright holder for this preprintthis version posted March 18, 2026. ; https://doi.org/10.64898/2026.03.16.712132doi: bioRxiv preprint 11 However, most of the produced grains are transported to other regions for livestock feed 299 production. 300 As reported by Wiedemann et al. (2017), strategies to reduce the environmental impact of 301 feed include replacing grains used in chicken feed and improving the feed conversion ratio 302 (FCR) through genetic improvement. The previous study reported reductions in greenhouse gas 303 emissions and fresh water consumption of 3-4.5 percent and 5 percent, respectively, with an 304 improvement of 0.1 in FCR. McKay et al. (2000) noted a yearly improvement of 0.02 in FCR 305 over the last 30 years, resulting in a reduction of 0.6 kg feed requirements. By improving FCR, 306 the impact on feed production is reduced. Costantini et al. (2021) reported that the feed 307 conversion ratios (FCR) of poultry strongly influence the environmental impact of the entire 308 supply chain. Therefore, improving FCR in broilers is ranked as the top priority to achieve more 309 sustainable production. Dietary alterations, including reducing crude protein intake and 310 optimizing amino acid balance, can lower FCR and reduce manure emissions (Wiedemann et al., 311 2016). Also, improved FCR could reduce the need for arable land. This could reduce pressure on 312 water and arable land resources and ultimately lower impacts from broiler chicken production 313 farms. In another study, Leinonen and Williams (2015) reported that a low-protein diet coupled 314 with protease improved the environmental performance of broiler chicken production. Ogino et 315 al. (2021) reported that a low-protein diet, along with crystalline amino acids, reduced nitrogen 316 excretion and consequent ammonia emission from poultry manure. Similarly, the use of specialty 317 feed ingredients (SFI), such as supplemented AA and phytase, significantly reduced the global 318 warming potential, eutrophication, and acidification potentials (Kebreab et al., 2016). Such 319 improvisations are crucial for the sustainability of the broiler chicken industry. However, 320 Tallentire et al. (2017) reported that the degree of flexibility to simultaneously reduce several 321 environmental impact categories differed across regions, due to the different feed ingredients 322 available in each region. Besides, Tallentire et al. (2017) and Costantini et al. (2021) reported 323 that the lower the age at slaughter, the lower the environmental impacts of broiler chickens. In 324 the present study, the slaughter age was 42 days; therefore, reducing it to 30-32 days can be 325 explored in future research. 326 After feed use, transportation, and electricity consumption accounted for the largest 327 proportions of the global warming potential and other impact categories in the broiler chicken 328 production system. In the present study, feed and day-old chicks were transported over a long 329 .CC-BY 4.0 International licenseavailable under a (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made The copyright holder for this preprintthis version posted March 18, 2026. ; https://doi.org/10.64898/2026.03.16.712132doi: bioRxiv preprint 12 distance from the source to the broiler farms. The dependence of broiler farms on external 330 suppliers for feed and chicks, due to the absence of local hatcheries and feed manufacturing 331 facilities, results in long-distance transportation of these inputs, which can be a significant source 332 of environmental impact. As the broiler chicken industry is heavily dependent on concentrate 333 feed, strengthening local feed production and supply chains will reduce the environmental 334 impact of feed transport. Similar findings have been reported by Wiedemann et al. (2017), who 335 reported that the grow-out phase contributed the largest proportion to the environmental impact 336 after feed use. To reduce the environmental impact of transportation, it is recommended to 337 strengthen the local feed production (Dekker et al., 2013; Thévenot et al., 2013). Also, a poultry 338 hatchery should be established in the region to produce chicks and supply them to local farms. In 339 addition, suitable climate-specific housing design, quality equipment, proper ventilation, and 340 installation of solar panels for on-farm energy use can lower the environmental impacts of 341 electricity consumption (Thévenot et al., 2013). Wiedemann et al. (2017) and Ogino et al. (2021) 342 suggested energy production from poultry manure/litter as a way to reduce emissions and lower 343 energy demand from production; however, further analysis is warranted in this area. Therefore, it 344 is essential to employ a multi-criteria approach that considers both environmental impacts and 345 economic considerations to improve the sustainability of broiler chicken production. 346 The LCA of poultry meat and egg production is well documented in North America and 347 Europe (Costantini et al., 2021). While a precise comparison with studies from other countries is 348 difficult, a broader overview can be obtained and may assist in improving the broiler chicken 349 production system in the future. Hence, a comparison of the global warming potential of the 350 present study with already published studies is presented in Table 7. Although on the higher 351 side, the findings of the present study fall within the range of previous studies. 352 Giannenas et al. (2017) reported that land use and land-use change (LULUC: direct and 353 indirect)-related emissions significantly affected the environmental impacts of the broiler 354 production system. In addition, differences in protein content in the diets and in their production 355 areas and productivity also affect the environmental footprint of a poultry production system 356 (Prudêncio da Silva et al., 2014). Similarly, production systems and slaughter age of broiler 357 chicken had significant effects on environmental footprints. Leinonen et al. (2012) reported that 358 the organic chicken production system has higher acidification and eutrophication potentials than 359 the conventional production system. Ogino et al. (2021) reported that slaughter age was 360 .CC-BY 4.0 International licenseavailable under a (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made The copyright holder for this preprintthis version posted March 18, 2026. ; https://doi.org/10.64898/2026.03.16.712132doi: bioRxiv preprint 13 significantly correlated with the acidification potential, eutrophication potential, and energy 361 consumption, but not with greenhouse gas emissions. It should be noted that different production 362 systems have different advantages in terms of animal welfare, meat quality, and ecosystem 363 biodiversity. An organic chicken production system promotes and enhances the health of the 364 agroecosystem, including biodiversity, biological cycles, and soil biological activity. With a 365 focus on holistic health management and a biologically active soil, organic chicken farming 366 strives to improve the health and welfare of the birds, meat quality, and environmental 367 sustainability. 368 Actionable point 369 The current study is the first to use the LCA approach to assess the environmental 370 impacts of India's broiler chicken production system. However, as with any study, there are 371

discussed in the following section that require further research. Nevertheless, the 372 study's findings suggest that improvements can be made in broiler chicken feed production and 373 the supply chain, as these processes significantly contribute to environmental impact. González-374 García et al. (2014) reported that there are obvious advantages associated with resource-use-375 driven impacts, including reduced transportation, reduced integration of energy-rich feeds, and 376 no land transformation. Promoting the use of locally produced animal feed will have lower 377 environmental impacts (Baumgartner et al., 2008). Moreover, establishing a poultry hatchery in 378 the production region will also reduce the environmental impacts of the broiler chicken 379 production system. The other improvement action may include installing a rooftop solar system 380 to harness solar energy, in addition to improvements in housing design and equipment. 381 Therefore, to reduce its environmental burden, several managerial measures have been proposed, 382 such as the use of organic fertilizers, composting, and incineration. This aspect warrants further 383 research, particularly in humid subtropical climates. 384

of the current study 385 To examine the environmental impact of the broiler chicken production system in India, 386 the current study used primary and secondary data. The authors collected the primary data 387 through personal visits to broiler farms, while the background data were sourced from the 388 Ecoinvent version 3.0 Life Cycle Assessment (LCA) database. The Ecoinvent database primarily 389 comprises global data, and hence, the closest data points were used to substitute the global data 390 for local representation. However, for energy-intensive processes such as transportation and 391 .CC-BY 4.0 International licenseavailable under a (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made The copyright holder for this preprintthis version posted March 18, 2026. ; https://doi.org/10.64898/2026.03.16.712132doi: bioRxiv preprint 14 electricity, the Ecoinvent database is representative of India. Also, poultry manure was not 392 included in the system boundary in the present study; previous studies have reported its 393 significant contribution to acidification and eutrophication potential. 394 5. Conclusion 395 Chicken meat is a crucial component of human nutrition and is expanding steadily 396 worldwide. In India, chicken accounts for 50 percent of total meat production and is the meat 397 that Indian consumers consume the most. The broiler chicken industry in India is vertically 398 integrated and uses modern technologies. The industry is consistently growing at 8-10 percent 399 annually and is expected to continue growing. Although LCA of broiler meat has been 400 extensively studied globally, no research has focused on the broiler chicken production sector in 401 India until now. The present study assessed the environmental impact of broiler chicken meat in 402 India. The primary causes of adverse environmental effects and resource depletion have been 403 found to be feed production procedures, followed by transport and electricity processes. In the 404 feed, maize production is the main environmental hotspot. The environmental impacts per kg 405 live weight are in agreement with those reported in previous studies. The study estimated a GWP 406 of 3.77 kg CO2-eq per kg of live weight, with a cradle-to-farm-gate system boundary. The 407 environmental impact findings published across countries differ widely, largely due to system 408 limitations, rearing conditions, the geographic location where the study was conducted, and data 409 quality. Nonetheless, there is still room for further reductions in environmental impacts in broiler 410 chicken production in India. Accordingly, the present study proposed actionable steps to reduce 411 further the environmental burdens of broiler meat production, including improved feed 412 production, optimized transportation and electricity use, reduced age at slaughter, and genetic 413 improvement. However, additional investigation is required to ensure these possible 414 advancements, particularly in the Indian context. To increase the sustainability of the broiler 415 chicken business in India, the findings of this study are relevant to both academics and 416 policymakers. 417 Conflict of interest 418 None 419

420 .CC-BY 4.0 International licenseavailable under a (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made The copyright holder for this preprintthis version posted March 18, 2026. ; https://doi.org/10.64898/2026.03.16.712132doi: bioRxiv preprint 15 The authors sincerely acknowledge the cooperation and support of the broiler farms, which 421 generously provided the primary data for the study. Also, the authors acknowledge the support of 422 The Energy and Resources Institute, Delhi, for collaborating in this study. 423 Funding 424 The work was supported by the ICAR-Poultry Seed Project, ICAR Research Complex for NEH 425 Region, Nagaland Centre, Medziphema-797106, India (PIMS Code: OXX01915). 426 Data availability statement 427 The data that support the findings of this study are available on request from the corresponding 428 author. 429

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It is made The copyright holder for this preprintthis version posted March 18, 2026. ; https://doi.org/10.64898/2026.03.16.712132doi: bioRxiv preprint 20 570 Table 1: Inventory data of the six different broiler production facilities 571 Unit 1 Unit 2 Unit 3 Unit 4 Unit 5 Unit 6 Chicks raised per cycle (42 days) 13500 18833.3 9333.33 17666.67 21666.67 20666.67 Number of cycles per year 6 6 6 6 6 6 Total chicks raised in a year 81000 113000 56000 106000 130000 124000 Mortality% 0.018 0.02 0.025 0.022 0.021 0.023 Average adult body weight (kg) 2.74 2.69 2.72 2.63 2.66 2.64 Total live body weight in a year (kg) 215829.3 298512.4 148656.4 272491.5 337818.8 320299.38 Total feed used in a year (kg) 401413.3 563464.9 276094.5 500541.4 639290.8 602270.84 Feed Conversion Ratio 1.86 1.89 1.86 1.84 1.89 1.88 Diesel in a year (litres) 5845 6826 4740 5240 5345 5043 Paddy husk in a year (kg) 6200 5900 4250 5300 5050 5300 Water used in a year (litres) 290800 422000 211000 423000 513000 485000 Electricity in a year (kWh) 11996 13200 8100 11600 11700 11200 Transport day-old chicks in a year (t- km) 810 1130 560 1060 1300 1240 Transport feed in a 100353.4 140866.2 69023.61 125135.3 159822.7 150567.71 .CC-BY 4.0 International licenseavailable under a (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made The copyright holder for this preprintthis version posted March 18, 2026. ; https://doi.org/10.64898/2026.03.16.712132doi: bioRxiv preprint 21 year (t-km) 572 573 574 575 576 577 578 579 580 581 Table 2: Average input used for production of one kg live weight broiler chicken# 582 Input Amount used per kg live weight produced Feed (kg) 1.87 Diesel (litres) 0.02146 Paddy husk (kg) 0.02079 Water (litres) 1.523 Electricity kWh) 0.44047 Transport day-old chicks (t-km) 0.00396 Transport (t-km) 0.4845 # Average of six broiler production farms 583 584 585 586 .CC-BY 4.0 International licenseavailable under a (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made The copyright holder for this preprintthis version posted March 18, 2026. ; https://doi.org/10.64898/2026.03.16.712132doi: bioRxiv preprint 22 587 Table 3: Aggregated feed composition data for broiler chicken production farm 588 Ingredients % For 1000 kg of feed For 1.87 kg of feed Maize 603.40 1.13 Palm Oil 20 0.037 Soybean Meal 292.0 0.55 Fish Meal 50.0 0.093 Limestone 10.0 0.018 Di Calcium Phosphate 12.0 0.022 Methionine 1.0 .008 Salt 3.60 .006 Trace Mineral Mix* 1.50 0.0028 Vitamin premix** 1.50 0.0028 Toxin binder 5.0 0.0093 Total (kg) 1000 1.87 589 590 591 592 593 Table 4: The impact categories and their units assessed in this study 594 Impact category Measurement Units Global warming potential kg CO2-eq Stratospheric ozone depletion kg CFC11-eq Ionizing radiation kBqCo-60-eq Ozone formation, human health Kg NOx-eq Fine particulate matter formation kg PM2.5-eq .CC-BY 4.0 International licenseavailable under a (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made The copyright holder for this preprintthis version posted March 18, 2026. ; https://doi.org/10.64898/2026.03.16.712132doi: bioRxiv preprint 23 Ozone formation, terrestrial ecosystem kg NOx-eq Terrestrial acidification kg SO2-eq Freshwater eutrophication kg P-eq-eq. Marine eutrophication kg N-eq Terrestrial ecotoxicity kg 1,4-DCB Freshwater ecotoxicity kg 1,4-DCB Marine ecotoxicity kg 1,4-DCB Human carcinogenic toxicity kg 1,4-DCB Land use m2a crop-eq Mineral resource scarcity kg Cu-eq Fossil resource scarcity kg oil-eq Water consumption m3 595 596 597 598 .CC-BY 4.0 International licenseavailable under a (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made The copyright holder for this preprintthis version posted March 18, 2026. ; https://doi.org/10.64898/2026.03.16.712132doi: bioRxiv preprint 24 Table 5: The environmental impact of one kg live weight broiler chicken produced 599 Impact category Reference Unit Result Global warming potential kg CO2-eq 3.77 Stratospheric ozone depletion kg CFC11-eq 0.00002 Ionizing radiation kBqCo-60-eq 0.022 Ozone formation, human health Kg NOx-eq 0.013 Fine particulate matter formation kg PM2.5-eq 0.0071 Ozone formation, terrestrial ecosystem kg NO x-eq 0.013 Terrestrial acidification kg SO2-eq 0.016 Freshwater eutrophication kg P-eq-eq. 0.00028 Marine eutrophication kg N-eq 0.0067 Terrestrial ecotoxicity kg 1,4-DCB 9.11 Freshwater ecotoxicity kg 1,4-DCB 0.012 Marine ecotoxicity kg 1,4-DCB 0.013 Human carcinogenic toxicity kg 1,4-DCB 0.026 Land use m2a crop-eq 4.63 Mineral resource scarcity kg Cu-eq 0.012 Fossil resource scarcity kg oil-eq 1.09 Water consumption m3 0.047 600 601 .CC-BY 4.0 International licenseavailable under a (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made The copyright holder for this preprintthis version posted March 18, 2026. ; https://doi.org/10.64898/2026.03.16.712132doi: bioRxiv preprint 25 Table 6: Contribution of different feed ingredients to the environmental impact of the broiler 602 chicken production system 603 Unit Feed Maize Palm oil Soybean meal Fish meal Global warming potential kg CO2-eq 2.10 1.68 0.08 0.27 0.05 Terrestrial acidification kg SO2-eq 0.01 0.008 0.0002 0.001 0.0004 Terrestrial ecotoxicity kg 1,4-DCB 3.72 3.26 0.071 0.20 0.18 Land use m2a crop-eq 4.46 2.13 0.057 2.27 0.0007 Fossil resource scarcity kg oil-eq 0.39 0.31 0.002 0.05 0.02 Water consumption m 3 0.04 0.009 0.001 0.02 0.006 604 605 Table 7: Comparison of cradle-to-farm gate climate change impact (GWP) of broiler chicken 606 production systems of different countries published in the literature 607 Country System boundary GWP (kg CO 2-eq) Reference Brazil Cradle to farm gate 2.70 Da Silva Lima et al., 2019 Greece Cradle to farm gate 3.92 Giannenas 2017 Italy Cradle to farm gate 3.84 Cesari et al., 2017 France Cradle to farm gate 2.2 to 2.7 Prudencio da Silva et al., 2014 .CC-BY 4.0 International licenseavailable under a (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made The copyright holder for this preprintthis version posted March 18, 2026. ; https://doi.org/10.64898/2026.03.16.712132doi: bioRxiv preprint 26 Brazil Cradle to farm gate 1.4 to 2.06 Prudencio da Silva et al., 2014 European Union Cradle to farm gate 3.43 Leip et al., 2010 UK Cradle to farm gate 3.087 Leinonen et al., 2012 France Cradle to farm gate 3.12 Baumgartner et al.,2008 Australia Cradle to slaughterhouse 1.8 to 2.2 Wiedemann et al., 2017 608 609 .CC-BY 4.0 International licenseavailable under a (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made The copyright holder for this preprintthis version posted March 18, 2026. ; https://doi.org/10.64898/2026.03.16.712132doi: bioRxiv preprint 27 Figure Captions 610 Figure 1: Location of the study area in India (Karbi Anglong district of Assam state and 611 Dimapur district of Nagaland state) 612 Figure 2: Climate conditions of the study region 613 Figure. 3: A schematic representation of the broiler production system in India 614 Figure 4: Methodological framework of LCA: phases of an LCA (source: ISO14040, 1997E) 615 Figure 5: System boundaries and flow diagram of the broiler production system under Life 616 Cycle Assessment 617 Figure 6: Contribution to greenhouse gas (kg CO 2-eq/ kg live chicken) emission by different 618 components in broiler chicken meat production in India 619 Figure 7: Contribution (%) of various inputs to different impact categories 620 621 .CC-BY 4.0 International licenseavailable under a (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made The copyright holder for this preprintthis version posted March 18, 2026. ; https://doi.org/10.64898/2026.03.16.712132doi: bioRxiv preprint 28 622 623 Figures: 624 625 626 Figure 1: Location of the study area in India (Karbi Anglong district of Assam state and 627 Dimapur district of Nagaland state) 628 629 630 631 .CC-BY 4.0 International licenseavailable under a (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made The copyright holder for this preprintthis version posted March 18, 2026. ; https://doi.org/10.64898/2026.03.16.712132doi: bioRxiv preprint 29 632 Figure 2: Climate conditions of the study region 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 .CC-BY 4.0 International licenseavailable under a (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made The copyright holder for this preprintthis version posted March 18, 2026. ; https://doi.org/10.64898/2026.03.16.712132doi: bioRxiv preprint 30 650 Figure. 3: A schematic representation of the broiler production system in India 651 .CC-BY 4.0 International licenseavailable under a (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made The copyright holder for this preprintthis version posted March 18, 2026. ; https://doi.org/10.64898/2026.03.16.712132doi: bioRxiv preprint 31 652 Figure 4: Methodological framework of LCA: phases of an LCA (source: ISO14040, 1997E) 653 654 .CC-BY 4.0 International licenseavailable under a (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made The copyright holder for this preprintthis version posted March 18, 2026. ; https://doi.org/10.64898/2026.03.16.712132doi: bioRxiv preprint 32 655 Figure 5: System boundaries and flow diagram of the broiler production system under Life 656 Cycle Assessment 657 658 .CC-BY 4.0 International licenseavailable under a (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made The copyright holder for this preprintthis version posted March 18, 2026. ; https://doi.org/10.64898/2026.03.16.712132doi: bioRxiv preprint 33 659 Figure 6: Contribution to greenhouse gas (kg CO 2-eq/ kg live chicken) emission by different 660 components in broiler chicken meat production in India 661 662 663 .CC-BY 4.0 International licenseavailable under a (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made The copyright holder for this preprintthis version posted March 18, 2026. ; https://doi.org/10.64898/2026.03.16.712132doi: bioRxiv preprint 34 664 Figure 7: Contribution (%) of various inputs to different impact categories 665 666 667 668 669 670 671 672 673 674 675 676 .CC-BY 4.0 International licenseavailable under a (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made The copyright holder for this preprintthis version posted March 18, 2026. ; https://doi.org/10.64898/2026.03.16.712132doi: bioRxiv preprint