Funding for this research was provided by:
Biotechnology and Biological Sciences Research Council (BB/M028291/1, BB/J004316/1)
Svenska Forskningsrådet Formas (2014-01840)
Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (291815)
Received: 24 September 2019
Accepted: 17 February 2020
First Online: 24 February 2020
Ethics approval and consent to participate
: All animal work was reviewed by the Animal Welfare & Ethical Review Body at the Roslin Institute. No work involved experimentation on live animals. All material was collected at the end of the breeding cycle or from embryos after euthanasia using a schedule 1 method as described in the Animals (Scientific Procedures) Act 1986 (UK).
: Not applicable.
: The authors declare that they have no competing interests, with the exception of RP and MS who are employees of the EW group and Lohmann Tierzucht respectively.