I once had a bird that had a horrible injury -- possible from a predator and probably made worse by pecking by the other hens. Her chest was torn open and and skin was falling off and it looked like I could see her bones. I took her to a vet friend who didn't know chickens but thought I should surrender her because she looked so horrible and didn't look like she could survive. We were off for vacation and I just couldn't bear to kill her. (We are vegetarians and enjoy our birds as pets.) We decided to bring her in a dog crate and keep her in my inlaws basement while we visited. It turned out the isolation and separation from her sisters was all she needed. She healed up and, once she returned home, lived many more happy years. Trust your instincts when dealing with your birds!