Put one of the roosters in a live trap/cage and hide it in the bushes about 50 yards from the chicken coop before sun up. EDIT: Make sure you hide the rooster good enough that the coyotes have to get real close to the cage. They will pay a lot of attention investigating the rooster and therefore will be distracted when it comes time to draw your bow.
Conceal yourself in full camo about 15 yards UPWIND from the rooster with bow in hand.
The Coyotes that are doing this are probably habitual about eating chickens and easy meals.
When the sun starts to rise the rooster will start his cockle-doodle-doo routine.
The coyotes will think one of those easy meals has wondered off and now is an easier meal.
Once again, Make sure you are up wind.
I've personally taken many a coyote, fox, and bobcats with this method.
If you shoot one, stay put. There very well might be another hungry belly not far from the dominate yote. The rooster will go nuts when he's got a preditor trying to get at him through the cage.
Good luck,
Todd