Please allow me to explain how this works. Not trying to be a know it all, but I`ve dealt with this enough to know the drill.
Several posters have said the key words, "when he`s old enough". That`s just it. A mature cock will dominate any hen and any younger rooster. That is until he is overpowered by a younger, but still mature cock. Maturity is the key and a young cockeral will be tormented by older pullets or hens. It`s simple. A mature cock is in charge, a young cockeral is a wimp by comparison, even to the ladies. Size has little or nothing to do with it.........Pop