I do not think Cadjien meant as you understood it. The "in the wild part" may be throwing meaning off.As a person with 30 years of experience studying just about every type of wild game fowl on the North and South American continents, I would have to firmly disagree with your statement. Wild birds regardless of kind, almost never fight over territory. Fighting among wild birds is strictly a method of establishing dominance with in a flock, and never result in intentional death. Wild fowl have a hard enough time surviving against the trials of nature. They would quickly go extent if they went around other members of their own flock. This is not to say that eventual death will not occur as a result of injuries sustained in battle or intentional starvation as a result of losing (common in older alpha males); but it is clearly not the intent of the battle to end up in death, but to establish dominance. The establishment of dominance is necessary and essential in nature to assure that the strongest genes survive.
Unlike humans, animals do not have the capacity to hate and make a decision to kill; they are simply following their instincts to survive and strengthen their group (flock, herd, etc.). It is entirely unnatural for wild birds to fight to the death within a flock. There are predatory birds that do kill to eat, but this is not what we are talking about. Humans have learned how to manipulate an animals instinct through training and selective breeding to cause animals to exhibit unnatural behavior, but there are studies that show that, even these specially bred animals, if left alone in a natural environment, will revert back to their natural instinct within a single generation.
In my area numerous bird (and fish) species defend discrete territories and that is mostly but no always done by males. Seldom is real harm done although on rare occasions damage to eyes does occur. Only bird species I know of that occasionally fights for keeps is the painted bunting but I am not familiar enough with that t say if it is of similar nature to that exhibited by gamefowl. Some fish may fight for keeps and one might be surpised to know species doing that when they are so common in some streams. They do so becuase they breed for only one breif season and get no second chances.