These are 3 different pullets. We have a large coup with about 160 3+ months old chickens who free range during the day in a very large (bout 1/4 acre) fenced yard we closed for them. about 110 are pullets, the rest are (will be) roosters. The problem is with 10 of them. We also see that some of them pick each other's feathers and chew on them while they have unlimited feed & grass available. Can someone give me an advice as to what it may be and what will be the best way to fix it? We are building another coop for them. Once it will be ready we will separate the pullets from the roosters. It will be in the next week or two.