I have 6 chickens total and the ones that are darker colored are losing there feathers on there back towards there bottom. My white chickens are fine though. This has been going on for about a month and now that spot on there back towards there bottom are completely bald. I have a pic but i'm not sure how to add it to here. Here is the Pic Not that good of a pic but it was dark when i was taking it. I will try to get a better one.