I do understand that chickens jockey for space at night, but what I'm going to describe goes a bit toward the savage.
I have a Barred Rock named Janie who is a fairly nice chicken, pretty high up in the pecking order, in good health and feather. She doesn't bully the other hens unduly during the day, but once on the roost at night and she will be merciless about pecking whomever is next to her (except, of course, Russell Crow the rooster). Three of my hens have begun to sleep in the next boxes, and it's just when I saw her going after a fourth bird tonight that I put together the nest box behavior with her pecking. They are hiding from HER!! Okay, that may seem a bit slow on my part I know, but there it is. This has been going on for a few weeks, and I have not been diligent about nest box exclusion. However, this needs to change.
A couple facts: I have nine birds and one rooster. The coop is 8X12, with the roosts 8 feet across the short wall. They are about 14 and 17 inches off the floor respectively. The roost bars are 6 inches apart. Two of the hens are Brahmas and fairly husky.
It seems to me that ought to be enough space for this ol' gal. I had the thought that a third roost bar, a bit higher than the others and small enough for her and maybe Russell might get her to stop this behavior. I had an arrangement like that before the roost bullying started, though I don't remember if she was reliably on it with him (he definitely went to it).
Has anyone had to solve this kind of problem? What did you do? Any ideas welcome, and thanks so much.