I always suggest you keep as few roosters as you can and still meet your goals. That’s not because you are guaranteed problems with more roosters, just that problems are more likely. I also do not believe in magic numbers such as ratios of hens per rooster or space per chicken. There are so many unique things about us and the way we keep chickens that what numbers work for one person may not work for others.
I don’t know how old your flock is but it certainly sounds like they are quite young. A lot of people confuse a flock of hens and roosters with a flock of pullets and cockerels. A flock of mature adults is generally pretty peaceful but a flock of adolescents, even with some adult supervision, not so much. With no adult supervision it can get even wilder. It’s quite possible a “peaceful” flock is more of a long term outlook for you than in the immediate future. A flock of cockerels and pullets going through puberty is not necessarily for the faint of heart.
Cockerels practically always mature faster than pullets, though different cockerels mature at different rates. The cockerels have hormones driving them crazy and they have little control over those urges. It’s not all about sex either, the mating act is probably more about dominance than pure sex at any age but certainly during adolescence. The one on the bottom is accepting the dominance of the one on top, either willingly or by force. The pullets have not matured enough to know what is going on and cooperate and the cockerels are bigger, so at this age it is usually by force. I saw a 13 week old pullet willingly accept a 13 week old cockerel once, but that is extremely rare. Mature roosters have perfected their technique and have better control of those hormones. Mature hens generally do their part willingly so the flock usually becomes very peaceful eventually.
My goals, set-up, and management techniques are different than yours so I’m not going to suggest you do it the way I do it. What I suggest is that you remove all the cockerels you are not going to keep as soon as possible. Whether that leaves you with one of none is up to you but I certainly would not keep more than one right now. Get rid of all of them at the same time. There will be some rearranging of the pecking order, even at that age, but at that age it should not be very bad. You might not notice any real difference. You also should not get as attached to them if you do it now. Waiting can make it harder on you.
I find it hard to make specific recommendations for numbers because we are so unique in flock make-up, management techniques, and climate. In Indiana you are likely to have some winter days that the outside isn’t available but you will probably not be integrating them so space isn’t normally as critical. Just give them as much outside access as you can. You might be surprised at what weather they will go out in.
That said, I agree that your space should handle about 25 to 30 mature adult hens without a problem. They are living animals so no one can give you absolute guarantees but I would not worry about that too much. I think you could add one rooster to that flock without any significant problems. You could probably have a total or two or maybe even three mature roosters in that space but I would not push it. The fewer roosters the better.
If you are going to be integrating chickens very much or having hens raise chicks with the flock I’d drop that number to maybe 20 to 25 total. Integration takes more room. A broody hen can normally handle the situation while she has her chicks but at some point she will wean them and leave them on their own to make their own way with the flock. This is where the extra room comes in really handy.
I’m always an advocate for not crowding them. I find the more I crowd them the more behavioral problems I have to deal with, the harder I have to work, and the less flexibility I have in dealing with problems that do show up. I like making my life easier rather than harder.
You might want to follow the link in my signature for my thoughts on space. I don’t give hard and fast magic numbers, mainly things to consider in flock make-up and management techniques.
Good luck!
