One of my 2 hens began losing her feathers in spring of this year. It followed two house moves in quick succession and quite a lot of upheaval, so I put it down to stress & added tonic to the drinking water. It didn't improve. A month or two later I noticed the bare skin on her belly was bright red and inflamed. The other hen was starting to lose feathers too. I assumed mites or lice, though I couldn't find evidence of either, and upped my housekeeping & delousing & changed their bedding material. The redness faded quickly, but the feathers didn't regrow. I thought they might need more protein and supplemented for this; the second hen regrew her feathers and seems fine, but the original is still missing about a third of her feathers. She is now looking very tatty and sad. She's missing tail feathers, fluffy bum feathers, the down from her face and all the feathers on her lower tummy. When she spreads her feathers anywhere there is pink skin visible that shouldn't be. It's been over 6 months now, & she lays daily, so surely not a moult? She's the dominant hen, so it's not feather pecking. When she preens she always leaves three or four whole feathers in her wake. They seem to fall out very easily. Any ideas?