The roosters will fight each other regardless of human contact; it is their natural instinct to fight. There are numerous chicken breeds that fit the gamecock type, but a gamecock is not in itself a breed. Today, cockfighting, like most blood sports, is illegal in most of the world, but exceptions exist. Ireland, England, the U.S., and Spain are well known for the quality of their game fowl.
A gamecock may undergo physical conditioning in preparation for a fight. The conditioning process is sometimes referred to as a "keep" and is designed to, among other things, tame the cock so that he can be handled during a fight. The primary purpose of a keep is to ensure that the bird is physically and mentally fit for its upcoming match, similar to the conditioning a boxer or wrestler goes through. The keep usually includes a special high energy diet as well as physical exercise.
Prior to physical conditioning, a gamecock that is to be fought or shown is often groomed. The comb and wattles is usually trimmed at around a year old. This process is called “dubbing. The feathers are sometimes groomed as well. The sickle feathers of the tail may be trimmed or any long feathers that a cock might trip on during a fight. In some cultures the feather trimming is much more extensive. The feathers of the chest and the back are sometimes shorn completely off. The reason for this extensive trimming is to help prevent a bird from overheating during a longer match. The reasons for this vary among individual game fowl enthusiast. Some trim their birds according to a tradition and others do it because they believe that losing the “bulky” feathers improves mobility during a fight.