We have seven hens. One of them is losing feathers on her underside/stomach, and seems to be pecking at herself a lot. The other chickens have begun pecking at her as well. For the past couple days she has been staying in the egg box all day and will only come out to eat if we make her. She seems kind of weak. One day a couple eggs had red blood spots on the outside so I thought it might be mites, but the eggs have bee clean ever since. I haven't been feeding them antibiotic feed but wonder if I should start.