“…Interestingly, the phenotypic differences between the two chicken breeds arise as early as the first few days of embryonic development (Clum et al, 1995;Burggren et al, 2004;Boerjan, 2004), potentially setting the stage for the breed-specific differences observed in latestage embryonic (Sato et al, 2006;Everaert et al, 2008), juvenile (Martinez-Lemus et al, 1999;Latimer and Brisbin, 1987;Odom et al, 2004) and adult (Martinez-Lemus et al, 1998;Koenen et al, 2002;Schreurs et al, 1995;McRae et al, 2006) phenotypes. Broiler embryos have faster overall development rates than layer embryos, which is first evident at 48ï h of development (Boerjan, 2004;Everaert et al, 2008).…”