A scientific case for revisiting the embryonic chicken model in biomedical research

Abstract The availability of fertilised chicken eggs and the accessibility and rapid development of the avian embryo, have been utilised in biomedical scientific research to make fundamental discoveries including of developmental processes that are common to all vertebrates, advances in teratology, the understanding of tumour growth and metastasis, angiogenesis, cancer drug assessment and vaccine development as well as advances in understanding avian specific biology. However, recent innovations in chicken transgenesis, genome engineering and surrogate host technology in chickens have only been utilised in a few of these fields of research, specifically some areas of developmental biology, avian sex determination and immunology. To understand why other biomedical fields have not adopted modern chicken transgenic tools, we investigated the non-technical summaries of projects granted in the UK under the Animals (Scientific Procedures) Act 1986 between 2017-2023 to assess when and how chicken embryos are used in research, and if they were considered as a Replacement model for other species. Highlights Evidence for a lack of uptake of the chicken embryo as a partial replacement model Case examples of the reduction in animal numbers when chicken models are used Proposed action plan for the avian developmental biology community Competing Interest Statement MGD is the originator and primary organiser of the Edinburgh Gallus Genomics and Embryonic Development Workshop (EGGED 2022 and EGGED2024), a resource mentioned in this article. Footnotes Declaration of interest MGD is the originator and primary organiser of the Edinburgh Gallus Genomics and Embryonic Development Workshop (EGGED 2022 and EGGED2024). https://www.gov.uk/government/collections/animals-in-science-regulation-unit