The crowing by your roos are a natural instinct of your chickens to let the hens know that he is in charge. Lesser roos won't crow as much unless they are trying to compete with the top rooster or they know that he had too many hens to take care of. He is the secondary rooster and will take care of the rest of the hens. The crowing by either is not a call for any preditor. Preditors usually go by visual or scent of your chickens. Available feed is another attractant. Keep your feed in a water tight container, change the bedding in the coop often with pine shavings or similar wood shavings to deter the smell of chicken poo and thier feed. Secondary is to place a tarp over the run to deter the hawks from seeing your chickens in the first place. They won't be interested in them if they can't see them. Good luck with these suggestions, I sure hope they work for you.
kartking22.