There's nothing like superstition in anything, what people do is to look for an animal that is more aggressive and offensive to be used in serving for this purpose, on a general form, you can discover that there are cocks that they are being aggressive than the others, same also we have some that are not, this is what you can find out in human as well, and have the high tempered being and many more, selecting a specific livestock species of local breeds could be more suitable in serving for this purpose because they have strong vigour.
Yes one of the first quality of the cock to be used in this kind of fight is the aggressiveness of the animal and their health status because using a gentle dull cock for this game will only amount in your animal getting injured for nothing and you still lose the game at some point also, although a number of their time, both animals in the game may give up without reaching the marked line to winning such a game and since there is a local game guideline for this it becomes a necessity to the animals to reach that benchmarks before being allowed to be declared the winner of the game.
I don't see anything like superstitions in this and the game has nothing out of the ordinary to make it native even though the game is played mostly in remote locations.