Effects of varying group sizes on performance, body defects, and productivity in broiler chickens

Abstract This study aimed to determine the changes in the performance, welfare, and productivity level of broiler chickens reared at various group sizes and non-grouped (single flock) under intensive field conditions. Two treatments were tested as a concept in all trials. In the GF (grouped flock) house, the grouping was applied at 6000 (GF 1 or large GF), 4000 (GF 2 or medium GF), and 3000 (GF 3 or small GF) broilers in the first, second and third trials, respectively, without changing the stocking density. In the SF (single flock) house, classical intensive rearing was applied without grouping the whole 20000 broilers during each of 3 trials (SF 1, 2, and 3). The results showed that large and medium GF chickens had higher BW than SFs at slaughter age. In SF 2 chickens, only HB level was significantly higher in the second trial (1.39 vs. 1.17). In the third trial, the FPD, HB, and BB scores of SF 3 chickens were higher when compared to small GFs at 1.85 to 1.41, 1.48 to 1.22, and 2.27 to 1.89, respectively. Chickens reared in GFs had more BW, FI, and better FCR and EPEF values when compared to SF chickens. BW, FI, and EPEF were observed to be lower—while FCR was higher—when SF chickens were compared to GFs. Upon considering the EPEF value along with welfare parameters, it has been observed that rearing chickens in groups of 3000 may increase productivity by up to 54.8% according to intensive conditions.