Thanks for mentioning the age. There is a world of difference in roosters and hens versus cockerels and pullets. At least yours are old enough that adolescence isn’t the problem. When did you see this problem develop? How long has it been going on?
If the entire feather came out it should regrow before too long. If part of the shaft is still in there, the feathers will not regrow until they molt.
In my experience a dominant rooster is not much of a threat to young chicks if they are introduced to him when the chicks are pretty young. He thinks they are his and is much more likely to help take care of them instead of harm them. Some of the hens might be a danger, that varies some too, but worry about the hens, not a mature rooster. Immature cockerels can be a danger though, maybe even more than the hens.
The eggs have to be incubated. The eggs won’t hatch just sitting in the nests, they have to be incubated. If a hen goes broody you can let her hatch, but don’t count on a hen going broody. It’s nice if it happens, but if you want to hatch eggs and have any control over that, get an incubator.
Many of us integrate chicks with the flock all the time. There are all kinds of different techniques to go about that. We do it with different aged chicks. Some people integrate very young chicks, some wait until they are practically grown. A lot depends on how and where you brood them and how much room you have. It’s not a simple yes or no answer, there are a lot of qualifications and if’s, but it is very possible to integrate chicks.
How much room do they have? I find most behavioral problems aren’t as bad if they have lots of room.
When I have a problem I try to determine if it is a flock problem or an individual chicken problem. That way I don’t treat the flock for an individual problem. You say every hen has a big bald spot. Some hens have brittle feathers, no matter how gentle the rooster is the feathers still break off. That’s usually a genetic thing, on how their body handles certain nutrients or vitamins. But if it is all your hens that is highly unlikely.
That sounds like a flock problem but it could be that one of the roosters has very bad technique. Your problem could still be just one of the roosters. Two roosters together can be more competitive than one by itself. Especially if room is relatively tight, it might be beneficial to separate one rooster if you can’t stand to get rid of him. Of course he will be upset. Is that worse than being eaten or given away? Sometimes we have to make trade-offs.
I’m not a believer in magic numbers like that 10 to 1 ratio for several reasons. One forum member keeps his chickens in a pretty natural setting and lets them form flocks. Hs average is around 7 hens per rooster. Plenty of people on here with one rooster and over 20 hens have barebacked and over-mating problems, even when they free range. Plenty of people don’t have over-mating oar barebacked problems with pretty small ratios. That 10 to 1 ratio comes from commercial hatcheries where they use the pen breeding system. They find that if they keep around a 10 to 1 ratio the eggs are fertile. If they have maybe 20 roosters in a pen with 200 hens practically all the eggs are fertile. It has nothing to do with roosters fighting or with hens being barebacked or over-mated. It has to do with fertility in the pen breeding method.
I still think your best bet it to remove one rooster. It may or may not solve your problem but it is the first step I’d take. Sometimes removing just one chicken can totally change flock dynamics.