We have 6 RIR pullets that were raised together and have always been in the same coop together. They are just about one year old. Recently we noticed that 5 of the 6 hens have broken feathers on their saddles. One is pretty thin-feathered down there, the others have varying degrees of broken feathers. And one hen looks just as pretty as ever. I have checked for parasites and dusted as a precaution. I'm thinking we have a feather picker and it's the one with perfect feathers. In all other respects the birds are normal...everyone eating, drinking, normal poop, laying usually 6 eggs per day. Any ideas???