Very interesting. Thank you.no its also on piligrams,west of england geese,cotton patched geese,shetland geese,steinbachers and with africans i know if they are males or females by week 1 and mix breeds are a bit harder to predict unless i know what breed the parents are ! For e.g i my male greylag mated with a embden and all the light coloured goslings with orange pale beaks were males and the females were same colour as toulouse goslings and when they got older the males were white and looked like white greylags and the females were same colour as normal greylags but they looked more heavier and all the offspring can fly