Hens have bare backs

[EggFarm65]

Please seek advice on the correct steps to do this if you aren't already adept at it. The last thing you'd want to do is injure your poor rooster.

I will, I have a special trimmer/grinder for my dogs. I had over 16 dogs in my lifetime and I trimmed all of their nails.

 

[EggFarm65]

I recently added a six months old dark Brahma rooster to my flock of 16 (six are still young pullets). I just noticed that four of my hens have bare backs, broken feathers but no scratches or bleeding. I can't find any mites or lice, I don't think they are molting since one of them is only seven months old and they all lay eggs. I do have one hen that likes to peck feathers but she usually leaves the seven months old alone. I believe it is my rooster. He is such a sweet guy so I hate to get rid of him but I don't want to have half naked chickens. Does that sounds like my rooster is the culprit or is it something else? I would appreciate any help.

I attached some pictures, Trudy's is pretty bad. Happy and Lucy are not as bad but also a concern. I couldn't take a pic of my Orpington she just looks like Trudy though. The rest seems to be fine.