The chickens are almost a year old; we've got 6 (3 RIR, 1 BR, 1 BsL, and 1 Silkie). We noticed it first with the Silkie. Some of the others (I haven't narrowed the culprits down yet) started plucking out the head feathers of the Silkie. I get home tonight and I see one of the RIR standing on another and plucking out her feathers on her back. Does this mean I have to get rid of the bullies? *Edit* They have about a 350 square foot area during most of the day to walk freely, not counting their coop.