I have an interesting development in one of my nest boxes. Parents are a gray normal **** paired to a gray opaline spangle hen. They are on their second round and produced two gray normal chicks the first round. They are now feeding two second round chicks that are just beginning to feather. It looks like the older chick will be a gray spangle. Strangely, the younger chick appears to be developing pin feathers on its head and upper wings that are yellow instead of white. I understand that double factor type 1 yellow face birds will have white faces, but when paired to a non yellow face bird shouldn't these produce all yellow face chicks? How could I have one yellow face chick when the pair has produced three white faced chicks? Does this make any sense? Thanks for the help!