Not a junglefowl, he is too large and he has light yellow legs. Junglefowl are small flightly birds, my hens were almost like bantams. The cocks don't get over four pounds if I remember correctly.
He isn't a American game because he is too bulky for one, and most gamefowl breeders would cringe at the thought of breeding something like that looks like that (no offense meant to the people who do own them, I'm just saying most gamefowl breeders would say "It's just a farm chicken"
). Games can be quite large in the body at times, but they are not bulky, and usually if they did have a body that large they would have legs long enough to match it. Plus, they tend to have longer tail feathers too, not to mention his short wings. Even dubbed, you would be able to tell what he is right off (in terms of a game chicken or not).
Marans have white legs, and he doesn't.
Partridge rocks are darker.
I think the closest to his breed is the Welsummers. He does have a light yellow leg color, but you have to take note of him being in the sunlight, which can distort the color. As well, as you have to take note of him being a hatchery bird, not selected for type/colors so at the same time leg color may alter (maybe that is in all Welsummers though? Not sure since I haven't had any experience with them personally). If you look on feathersite, you will see a few birds that have the same colored legs.
Looks VERY much like a Single Comb Brown Leghorn to me. I have a young brown leghorn that looks just like that. He could just as easily be a Welsummer though.
It's so hard to tell the difference between them, although Wellies seem to be a bit 'fatter'. It would be easier if you had a hen of the same breed, since Welsummers lay brown eggs and Leghorns lay white. Also, the leghorn hens' combs are floppy.
If people in your area are into cock fighting, that means they're into an illegal activity, since it was recently banned (for good reasons!).