I have been hatching baby chicks, I am supposed to have standard barred rock,& buff brahma bantams. All has been fine but the past two hatches I have had one all yellow baby chick hatch. I don't know where this is coming from, it is the same size as the other barred rocks, and should not be the buff brahmas as it is a clean legged chicken. Help I need to know what you think is going on here. Thanks