I have had trouble with feather pecking in my flock of hens for almost 8 months. I have 23 Black Star hens and 3 Orpington hens in the same coop. Almost half my hens have at least a small bald patch around their vent and/or back. Some have large bald patches. The feather pecking started last winter when we had a long Manitoba, Canada cold spell of minus 30 and colder and the hens were locked in a coop. Initially I thought the problem was having 3 roosters in the same coop which were constantly pouncing on the hens. I removed the roosters expecting the feathers to grow back, but they did not. I suspected that they may have mites, I have looked for mites on several occasions during the day and night and have not found any. Since spring the hens are allowed to free range for several hours a day. I only allow 1 rooster to free range with the hens at a time and I keep the roosters in a separate pen when the hens are not free ranging. I moved the hens to a new 10`x 12`coop to give them more room. I have tried keeping badly de-feathered hens in a separate pen and feeding them a boosted protein diet to grow their feathers back before returning them to the flock. I have tried separating suspect feather pecking hens. I have tried using anti-feather pecking gel products on the pecked hens. Everything that I have tried has had a minimal impact on the problem.