One of our banty hens has suddenly lost 3/4 or more of her feathers in the last few days! It looks like an extremely heavy moult all the sudden? We are in northern Illinois and I have never seen this happen in the many years that we have had chickens. We are putting her in the warm basement for now, but are sure wondering what is the matter. It has been cold here so not like a sudden warm up to have fooled her system. She had seemed healthy and normal up until this happened. Does anyone know what might have happened. We just have one other hen right now and she is fully feathered.