I've found my drakes will try to mate anytime if given the opportunity, but it's worse during the milder seasons. The chickens are in mortal danger around them no matter what.
Kathi is correct, two hormonal drakes going after chickens is a recipe for disaster. So long as their needs (other than procreation!) are met, and they aren't fighting, they'll be fine.
Will you be getting them some females, or just stay with a bachelor flock for now?