One of my hens has a large scab on her back. It happened because of my roosters' aggressive mating. I have removed my roosters and the wound is still not healing... even after one year! I tried Neosporin, and the feathers would begin to grow out, and then they would vanish. I think one of my chickens is pecking her back and not allowing it to heal. How do I prevent my chickens from pecking each other?