I have 10 hens and just recently culled 2 roos. I have 3 hens with bare spots on their backs and one with a bare back and the tops of her wings are bare from the roos. She was their favorite! Now that the roos are gone, how long will it take to grow their feathers back? I am a little worried because the skin looks almost dry and scaley on some of them. Is there anything I can do to speed up the process?