Very calculated they were. Several times the Silkie had the Sumatra pinned on his back, pecking the heck out of him, when the Sumatra got up, the Silkie would grab him by the back of his head, & start kicking him in the head. The Sumatra would flog at my silkie just to get kicked backwards, & pinned again.Yes, most adult roosters will and can fight. The difference in GENERAL is the technique. A few exceptions are always very real, we are working with animals after all. But gamefowl not only will have the urge to fight literally from birth, which no other breed has, but also their kicks and pecks are very much more calculated, planned, and deadly than any other chicken. I've seen my huge landrace male fight, what he does is basically hop and straighten his legs outward, literally, no other movement. While my ~4 month old aseel would have killed that hen, if all his kicks would have landed where he intended, and not on her back, because while he was grabbing on to her neck and kicking, she was panicking and running top speed trying to get away, but he didn't budge. He kept grabbing on, and kicking, until I separated them. Lastly, their whole build aids them to get the job done. Strong legs to kick the opponent, steel like beak for pecking, strong feathers for protection, small comb and wattles for no unnecessary injuries, and a low set tail so there's no resistance when they run at top speed
It all actually shocked me, that this happened.