A lot of the feather damage could be due to the fact that they are old feathers, and she was about to molt, but roosters can leave marks.
If I read your post correctly, you have removed the rooster, and kept the hens together. I hope that is right. It will be relatively easy to re-add the rooster in when you want. But adding a hen that has been by herself, is very difficult. I very seldom separate birds because it often causes more problems that it solves. And it can be a lot of monkeying around.
So if you want, you probably could put the rooster back in now. If she is molting, she will probably regrow the feathers, and look just fine for several months. You might check the rooster's feet, specially his feet, and toe nails. Many people file them to keep them from being so sharp.
And you might take a good look at your run. Is it a bare open space, whereas a chicken can see every other chicken 100% of the time. Well then you might add clutter, and hideouts to your run giving your hen space to get out of the sight of the rooster.
As to your question: some birds molt fast, and grow back fast, and some do not, and about drive you nuts. People do feed higher protein and in theory that should help, but really I have found it more to be 6 fingers on one hand, half a dozen on the other.
If your rooster is too aggressive, you might remove him permanently. Consider why you have him. Sometimes they are not worth the disruption to the flock.
Mrs. K