I've been pondering and wondering about it for a while, but last week I finally made the decision to rehome little Buttercup. She was simply not getting any rest from the other two girls and it was getting cruel. I've added tons of foilage, enrichment, distracions, but nothing seemed to work. They were at her all the time.
I found her an amazing new home (i had plenty of choice - it turns out adult hens are almost impossible to find) on a farm where they've had one lone male for almost two years. It was heartbreaking to see her go, but since then the entire atmosphere in the run has been a lot more chilled.
Prim keeps doing his thing of course, but the other two ladies have settled down a lot. Maybe the space just wasn't enough or maybe the simply saw her as faulty somehow. Last summer when they were still young they plucked her feathers until she bled.
I think it was the right move to make.