Today two of my roosters went at each other. They are in separate pens but can see each other and have never fought until today. Neither have hens with them as yet. By the time I heard them my White Leghorn was bloody and his wattle torn. The Black Australorp rooster didn't have a scratch on him. I grabbed the water hose to try and separate them but they didn't even slow down. I finally had to put up a board they can't see over to stop it. What could have caused them to go at it today?