I have two bantam cockerels that are about the same age as yours. From time to time they will do the same thing. (They don't peck at my hens on the comb or head, though.) My standard girls just throw the little guys off when they've had enough of their nonsense. My two cockerels do not fight. They sparred a good bit when they were chicks, but grew out of it when dominance/order had been established. I would concur that you probably want to keep only one if all of your chickens are standards as you don't need injured or stressed hens. (with our standard gals and banty roos, there hasn't been any issues - thus far)