I have one chicken that just keeps plucking feathers from the rest of my flock. It will eat them and so will the other chickens I don't think it's cause of lack of protein they get layer feed and I give them eggs and other treats. I looked for mites I don't see any. It's doesn't seem sick or anything. I threw some stuff down just in case it was cause of boredom that's not it either. I don't know what to do please help!