We had a bum feather picking problem for a while during the Winter. Through careful shifting within different flocks and use of blinders, etc, we've been able to stop the picking. That said we have gotten most of them to grow their tails back. Some however are completely bald back there and one is even missing most of the feathers up her back. My question is, is there any hope they will grow back? Or have they been pecked to a point of no return? The others who re-feathered are almost back to normal, while the others seem to be exhibiting Zero Growth. Im not sure when to give up and cull them. Any help would be greatly appreciated. Thanks.