2 hens out of 9 are losing some feather on their back from the rooster

[Deer lane farm]

Now today I see where they are losing their feather one of them was all wet and dark and smelly. I don't see any cuts or blood. What can this be? If the Rooster getting poop on the girls back. I smelt like it. I separated them for now. What should I do. Should I get rid of the Rooster? This doesn't happen to any of the other hens. Can I separate the Rooster and let him live by himself with the goats.
I love my Rooster but I can't have him hurting the girls. Could this be something else, some kind of infection? I don't see any thing but missing wet feathers.

 

[Eggcessive]

Can you try to dry out the area with pine shavings or sand? Hen aprons made out of a piece of a square piece of polar fleece with 2 wing slits are good for shielding their backs form over mating. You can limit the roosters time with the hens for awhile or separate him until he calms down a bit. Dull his spurs and beak tip with a file to cut down on his hurting them. Most roosters need 10-12 hens as a good ratio.