I keep games and have done so for a long time. This playing out like what occurs with a poorly managed flock. Option I would follow is to capture stags / cockerels and rehome those if they are not to be penned in location where they cannot get to each other and the elder male (unknown as to whether he is a cock or bullstag himself). A small flock / harem made up of an adult male (haram master) and a hen are two are the most interesting chickens you are likely to ever have. I make a point to keep one free-ranging group actually living on front porch just so I can watch their antics. In so many ways they operate like small flocks used to for keepers of chickens for several millennia.
Are you talking just game cockerels? I'm only asking because I had a dozen non-game cockerels living together in a grow-out pen for 3-4 months last year without any problems. I also had 7 brahma roosters housed together for several months a couple of years ago. No problems there, either. I didn't know if game birds were different in that way - more aggressive or not.
Aggressiveness and gameness are distinguishable and important to confinement of males. Both attributes vary by degree although some purist would not agree with that in respect to gameness. Aggressiveness is measure of how readily a given individual will attack another as well as how intensely. Gameness is a measure of much effort an individual will invest in defending its interest in the face of adversity. Some breeds rank low on both accounts where pecking order maintenance causes little damage to confined groups like with my American Dominiques and your Brahmas. Others like California Greys I used to have where constantly aggressive with their scrapping resulting in the damaging each others feathers. They had many short duration fights. I think aggressiveness is proportional to testosterone levels. For show purposes and to limit stress on hens I try to house such aggressive roosters separately. Gameness can vary such as with the same California Greys that are so willing to start fights are also inclined to back down if attacked themselves. The American Dominiques were willing to put more effort into a scrap once it started and usually prevailed against the more aggressive California Greys therefore the American Dominiques where more game. With my games, as young stags, they are comparable to American Dominiques with respect to aggressiveness but would often be willing to fight to the end even if pummeled down by a much larger American Dominique. The same games as bullstags and cocks where are also every bit as aggressive as Callifornia Greys in they will even take on a wild tom turkey and very game in they will fight one to the end even though the rooster has not even a snowballs chance in Hades of winning. Both attributes can be impacted by genetics and circumstances even within a breed. With my games, aggression can be suppressed in younger males by the presence of a clearly more dominant adult male while physical condition and potential benefits of winning can impact how much effort an individual will invest as gameness. Even a young game stag will give his all if he has a reasonable chance of winning exclusive mating rights to a harem.
I am only guessing that they starved; the next door neighbor said that there were about 10 chickens when the house was abandoned, and there were only 5 when we got there. We found several old bird carcasses about; I suppose I can never truly know what they died of. Hawk predation? Possible, although several carcasses were under the hen house (including several chicks). Dehydration? Perhaps. There is no natural source of water on the property. But it seems I have one, and the responsibility for their well-being comes with that.
