Is there a nutritional or other deficiency that can cause generalized feather loss in a flock? These chickens are about 12 weeks old. When they shake, I can actually see feathers flying off of them and I am finding a lot on the ground and in the coop. It is not just one or a few, but many of them. I have never seen this, but I'm wondering if it could be some kind of nutritional deficiency? They are on grower feed with a 19% protein level. I have checked for mites and lice and there doesn't seem to be any unusual pecking or problems among the flock.