Have you got males in with the hens?
It's usually the boys that fight and they will seriously injure or kill each other.
You need to sex and separate the boys from girls.
You can put things in to help distract them. Eg conifer branches, dust baths, cardboard boxes. Lots of places to hide and get out of each others way. Obstacles help to break their running attacks.
Rats will get in and kill them unless you use that strong small squared wire.