Chicken Missing Butt Feathers

[Weeg]

found a picture of the coop from a few weeks ago: View attachment 2596856

Do you know the dimensions? Is it an 8x8 or 10x10 run? Are they constantly in there, or do they get to free range? I think the problem is boredom, and cannibalism. I have an article in the shared book marks part of my profile that has a good list of boredom busters, you can see if that will help entertain them.