That happened over night? ooohhh..... Are your roosts un-even, like the ladder type? if so it could be the chickens above picking the feathers of the girls on the lower roost. Were there loose feathers under the roost? or none? if none, they were eaten by another chicken, itself, or something else...Thanks, I'm going to deep clean the coop and chickens to make sure it isn't a parasite. It's just so strange, and it happens overnight too. The hen in the picture was fine yesterday morning and when I locked them up tonight her feathers looked like that