I'm curious to know if you kept all females in your cages, or was it males pecking each other? After culling at 8-9 weeks, I plan to keep the males in the breeders with 3-4 females. A few extra males will be kept in with the layers, but only 1 male per cage. I'm hoping this will avoid fights.
A mixture to begin with but way before breeding season and it was both female and males doing the pecking. I used the pen as a grow out until I put them in a large pen (5' x 6' x 20') at that time I ran 5 males and 20 females per pen, each species. Total around 45 birds to the big pen.
These were Bob's, and Blues, yes, you can raise them together. Gambles and Valleys need to have their own pen as they will fight amongst themselves regardless of the numbers.
In the wild, and here in South Texas, Bob's and Blues run together in the late summer until breeding season. Then they pair up for breeding.
I have the same experince with mine in captivity, the difference being in captivity the males didn't tend to fight like they would in the wild. They would get in arguments but not fight to the death.
With Cots, I raised them in breeding cages, a pair to a cage. Had battery after battery for them. That's one of the reasons I quit raising them took to much time(always building cages) and space for them to be raised that way.
With any birds, if you overcrowd them or don't understand their requirements, you'll have problems.