For the past 2 months three of my 5 chickens are missing just the front neck feathers. I checked them for lice and mites and don't see anything. They are only about a year old. Any ideas? I made the pvc pipe food pail for them last year...could they're necks be rubbing on that and causing frictions. But it was fine last year . Some of the feathers look broken around the neck as well. I don't see anyone feathers picking. Have no idea. They aren't growing back either.