This is my second year raising chickens. Last year I had a variety of breeds 2 Black Sex links 4 Rhode Island reds,13 Brown leghorns, 2 buffs and 4 barred Plymouth. I bought them in late may and by October most of them had bare backs. I tried everything to correct the problem. Red light in the coop at night, Vicks on their tails, feeding them a small amount of cat food for extra protein, even making Chicken sweaters, nothing helped. Unfortunately in April this year our dog got in the coop and killed all but 8. Six of which I had already separated out because the were mean. Those six still do not have feathers on their backs, they are still separate from rest of the birds. In may this year I purchased 50 chicks 25 buffs, 22 White leghorns and 3 brown leghorns. The brown leghorns are losing the feathers. Any help would be greatly appreciated.