Breed is a manmade thing. Chickens have no concept of breed. Breed isn’t really relevant to your question unless some are from a strain of Games that have been bred for fighting. In that case you will have a problem, whether you have one hen or a thousand.
You’ll often see some magic numbers of hens to roosters given, 10 to 1 being a real common ratio. That has nothing to do with your situation. That 10 to 1 is what many hatcheries use when they use the pen breeding method, and is about fertility. They’ve discovered that if they want practically all eggs to be fertile they need to use that ratio, say 20 roosters with 200 hens in the same pen. It has nothing to do with roosters fighting, bare-backed hens, over-breeding, anything like that. If you house them in a different situation that ratio has no effect on fertility.
In my opinion how successful you will be in trying to keep those will depend on how much room you have. Very few of us have enough room. What often happens once the roosters reach maturity is that they determine how they rank, then each rooster gets his own harem. Each rooster establishes his own territory that does not overlap any other roosters. This way they can avoid each other.
One of our forum members, Centrarchid, keeps a lot of chickens this way. I don’t remember him quoting a specific ratio but sort of reading between the lines, I suspect your ratio of 40 hens to 7 roosters is more in line with what he keeps. That would make a good question to him. He has some interesting posts on the topic in this thread.
https://www.backyardchickens.com/t/1071793/free-range-only-no-feed/20#post_16587440
There is another option. Build a bachelor pad. If you house the cockerels and roosters together with no hens to fight over, they quite often live quite peacefully together.
You can try keeping them all together. They are living animals, no one can give you any guarantees about any of this. Just have a plan B ready in case you need it quickly. And be prepared for things to get pretty wild during their adolescent phase. The cockerels have hormones going wild and little if any self-control. The pullets are too immature to know what is going in and do their part. The adolescent phase can get pretty wild until they reach maturity.
