That totally blew my theory out of the water. Some of that sounded like mature hens attacking a cockerel. If the male being pecked is one that is only a year there might still be some of that going on but he should be holding his own by now. How sure are you that the injury was due to those hens pecking him? Could he have somehow just cut it on something sharp? Often chickens will peck a wound.
Like Mtnboomer I've observed that the ratio of hens to roosters isn't that important. I'm talking about actual observations, not what you read on this forum. I've had ratios less than 1 to 5 and the boys got along OK but they really had a lot of room. One took his harem and stayed away from the others during the day. The other two hung together but they knew which one was boss and shared a harem. Nothing wrong with getting more hens but do not expect that to stop fights between roosters or over-mating of females.
At that age the boys will determine which one is boss. That might be a fight to the death. That might involve some skirmishing and a lot of running away and chasing. There is only one way to know for sure. The more room they have the better but you don't get guarantees.
Hens can be bullies and they have their own pecking order. They want to be at the top. It sounds like your older hen is weakening and the others see her as a threat to the top position. If you put them together with lots of room they might work something out but I'd expect them to beat her up. She might or might not be killed or injured in that. I just don't now. There is also the chance that she will be ostracized by the flock and forced to make her way alone.
So you have two males that will probably fight if you put them together. They may or may not be able to work things out. You have two hens you don't trust with one of those roosters or with one of your favorite hens.
You can try putting them all together, just be around where you can observe. You can try keeping two flocks with that old hen and a buddy or two with that rooster with the injured comb with the others together. See what happens. You can continue with three flocks. You can get rid of those two brutish hens and try combining the remainder. You could also get rid of one of the roosters and try one flock, especially if you get rid of those two hens. Just all kinds of combinations. I can't tell you which one will work.
With any of these you can get more chickens if you wish but you'll have to integrate them. Don't expect that to cure any fighting between the roosters or between the hens. I don't know what your goals are but you might want to bring in a few young ones as five years is getting fairly old for a chicken. It's probably time to think about replacing some.
