Could you post photos to show how bad it really is? It’s not unusual for a hen to lose a few feathers during mating, perfectly normal. The area at the base of her tail can sometimes look worn or fluffy. It’s when the area becomes really bare that there is a risk. And as the others said, that risk is often exaggerated.
When I started my flock here, I had a couple of hens that did get pretty barebacked. I’d read a report that some hens just have brittle feathers, it’s a genetic thing. The feathers are so brittle that they break really easily, even of the rooster is pretty gentle. When I removed those pullets from my flock the problem went away. Since I removed those genetics from my flock, I have not had any really barebacked hens show up in later generations. You might give serious consideration as to whether you want to hatch any eggs from those specific hens in your flock.
It’s not always brittle feathers though. Sometimes either the rooster or the hen just does not have good technique and too many feathers are lost. Both male and female have a part to play in this. Sometimes the rooster is a brute. It’s not just the number of times the hen is mated that causes the problem, there is something else underlying it.
How old are yours? It’s not unusual for adolescents to be very energetic yet have horrible technique. This could be an underlying cause, but a temporary one because they will eventually mature. If yours are less than a year old, this might be the main reason.
If they are adolescents what can you do? You could isolate the pullets while they and the cockerel mature, especially if you don’t want hatching eggs from those specific pullets. There could be some pecking order/reintegration issues when you put them back together but with a dominant rooster that keeps peace in his flock and with them having adequate room, this is often not that big of a problem. If your new facilities are where they can see each other through wire the risk is even less. While integration can be serious and is something I try to avoid, that’s something else that can be exaggerated on here, especially it they have adequate room.
Something else you can try to buy a little time is to trim the cockerel’s toenails. They are a lot like your fingernails, with a quick that will bleed if you cut into it but the tip will not bleed if you cut it. I’m not saying totally cut them back, but just take the sharp tip off. Cut them straight across. I’ve used a Dremel tool for that with the disc you use for cutting metal. Even if you get a little too deep and they bleed some it should not be a permanent problem. It will probably disturb you more than him. Blunting his toenails will help reduce the damage he does while treading. By the time they grow back sharp they should have matured enough so the damage does not recur if this is the problem.
If the entire feather came out those feathers will grow back fairly soon. If a piece of the shaft is still in there, those feathers will not grow back until they molt.
I don’t know what is going on with your flock. Is it normal wear and tear or a serious problem? What are the real causes? Even with more information and photos it’s really hard to tell over the internet. I wish you luck solving it.
