Around October my 10 month old Marans based hybrid stopped laying. Despite being a hybrid that is supposed to lay through winter, I just put this down to a reduction in daylight hours and thought no more of it. She did lay two unexpected eggs last week, meanwhile my other girls have carried on laying beautifully. This morning I noticed she had a bald bottom so I picked her up and discovered she has next to no feathers at all between her legs! The area does't look sore or red. I've attached a photo but it doesn't show the full extent of the feather loss between her legs. So I checked for lice both on the hen and in the coop and can't see any evidence of parasites. I use DE as a preventative measure in the coop and dustbath. I don't think the other girls are pecking her because she is top chicken and I've never seen this behaviour in the flock. She is not broody and not going through a moult. I don't see any reason she could be stressed; they have a beautiful large run protected with electric fence. It's very rare I find any of her feathers in the coop/run. I suppose she could be eating them but she is being fed good quality layers pellets with limited treats. I'm am totally stumped! Does anyone have any ideas what this could be and how to treat it please??