These chicks (19) are being fed Starter/ Grower crumble feed once in the morning( 0700 )and in the evening (1700) with food available except at night in the coup. We have found that there are a couple that are very agressive and constantly go around pecking the others on the back near the tail feathers. I saw one today actually pick off a feather and eat it! Is there some deficsency (sp) in diet that could cause this or is it the room available. They have a small starter coup( 3x4) and a 6x8 covered run. Some of the chicks have started to get sores in that area. Even one of the perpetrators is getting a bad spot. not all get picked on and not all are pecking. We have isolated the ones with the worst problems and even removed one from the others that seemed to be the worst offender. Any suggestions or remedies would be appreciated.