One of my 3 hens is quite pale and losing neck feathers. With winter approaching I have my 3 hens and rooster with my 3 guineas. I've had a pretty bad mite problem but everyone seems to be getting better with that problem. This is buttercup. and its more like her feathers are thinning out. Maybe molt? They are all on a higher protine feed cuz the mite problem made them a bit skinny for my liking. I give them eggs and live meal worms. They free range for maybe 3hr on week days and most of the day on weekends.