I am having a real problem with bullying. I have a sweet friendly 20 month old Buff Orpington who is the only survivor of a fox attack last fall. I purchased 9 new chicks this spring (Wyandottes and Barred Rocks), 2 of which were "surprise" cockerels. Everybody was getting along well until a few weeks ago when I found the Buffy cowering in a corner, bleeding from her comb and head. I cleaned her up and put her in a dog crate in the coop. After her wounds healed, I let her out with the rest of the flock and 4 of her flockmates (led by the huge Rock roo) immediately and viciously attacked her. I'm certain they would have killed her if I wasn't right there. Back in the crate she went. A week later I tried again-same result. She's also molting.
Since that incident all h- - - has broken loose in the coop. Two of the smaller hens are missing all the feathers in their vent area. Some of the others are missing tail feathers. Oddly enough, the worst victim is the huge rock roo. All the feathers at the base of his tail have been pulled out and he has bleeding wounds in the area. I spray his wounds and the bare bottoms with Blue Kote every couple of days so the others won't see the wounds, but the feather pulling continues. Two of the bigger hens are also being overmated and have bare backs. I have never seen the roos fighting, and the smaller one is unscathed. I suspect one of the unwounded hens, but I'm not sure this hasn't turned into a free-for-all. As you can imagine, egg production is low.
They have a 12' x 8' indoor coop and a 12' x 16' outdoor coop. I can't let them free range, or they'll all end up like my last flock. They are fed Blue Seal Extra Egg 16% protein, free choice grit and oyster shell, and mealworms on occasion.