We bought ISA brown pullets from Tractor Supply back in March. It was the very first day they started selling chicks, and they ONLY had ISA browns at the time. So now they are about 7 weeks old and we've noticed that one of them is quite a bit darker than the rest- mostly dark red with very little white (only underneath), very unlike the rest that are lighter brown/white speckled. Yesterday we also noticed that near her rump, on each side there is one feather that is half white/half BLACK. Seems unusual because all the others have very white rumps! Just wondering if this is normal variation within the typical ISA brown coloring, or is it possible she is a different kind that got mixed into the ISA browns somehow (can that happen? it would have been at the "factory" not at TSC, because they had no other chicks yet).