We are new chicken keepers with four hens that are 8 months old. We have two barred rocks and two buff Orpingtons. They have all been together from the beginning and were doing well until a few weeks ago. We were getting 2 - 4 eggs/day even in winter. Over the past few weeks, the barred rocks have been pecking the buffs on the feet and in one case in the head. They have drawn blood and we have had to remove the injured buffs to recover. The barred rocks have starting pecking at me and my husband which is also new behavior. The hens have a decent sized run, roughly 60 sq.ft. with a dust bath and a roosting ladder that we built for them. The coop is adequately sized with two nest boxes. Any ideas on how to stop this behavior? The buffs are very docile and friendly, I hate seeing them injured.