Don’t take me wrong. That 10 to 1 ratio makes for a nice flock. But that ratio comes from commercial hatcheries using the pen breeding method. That’s where they may keep 20 roosters and 200 hen s in one pen. They’ve found under those circumstances they need a ratio about like that to keep fertility up. It doesn’t have anything to do with roosters fighting and not much to do with hens being over-mated or anything like that. I’ve had great success with three roosters and 15 hens and I’ve had problems with one rooster and many hens.
In a larger flock like yours, if they have a reasonable amount of space, three normal reasonably young roosters with normal vitality will have no trouble keeping all the hens fertile. Two could probably do it. Each flock and each rooster is different so I can’t give you absolute guarantees but it should work most of the time.
It’s possible you could get roosters that fight to the death, especially with certain breeds like game roosters, but what normally happens is that the roosters decide which is dominant and then reach an accommodation on how they take care of the flock. There will probably be less fighting and less vicious fighting if they are raised in the flock together, either as siblings or in a father-son environment, but even adults put together will usually reach an accommodation. In any circumstances try to give them a lot of room so the loser has plenty of room to run away. It can be interesting to see them working together. For example, I’ve seen the dominant rooster be the first out of the pop door in the morning checking things out while the subordinate is the last out, protecting the rear.
When they mature you will probably see the flock split up where each rooster has his own harem. That doesn’t mean that the rooster only mates within his harem. Any rooster could be the father of any chick from any hen. In a flock your size, you may even see some hens form their own sub-flock without a rooster.
When yours hit adolescence it will probably get real active. The boys will have their hormones flowing wild and likely won’t have much self-control. The pullets will probably mature a little slower and won’t have clue what’s going on so they don’t know how to do their part. If you can get through that adolescent phase the flock should settle down very well but it can be trying for a few months.
I know this doesn’t answer all your questions but maybe it’s a start. Each chicken as its own personality, each flock has its own dynamics, we keep them in totally different circumstances. I can’t tell you what will actually happen with yours. But if they have enough space and you can get through that adolescent phase without wringing the cockerels’ necks, they should settle down to a nice flock, whether with either three or four roosters.
