I have two hens one is healthy and one is sick. The sick one pulls out her own feather from her back and under her wings. They are all over the coop She is congested and wheezes, both eyes are sealed shut. I have also noticed that she shakes her head a lot. She has energy but look awful. She seams to eat and drink o.k. and I have been giving her vitamins. I have used poultry dust and 7 dust on her and the coop with no benefit and I have never seen any mites or eggs on her. She hasnt started laying yet. Could one problem cause all this or does she have multiple ailments? If I cant find a cure I think I will cull her.