The roosters have been fighting a lot lately. I'm sure it has something to do with trying to impress the hens and the pullets. (All of which are laying now--seems the fighting started when the pullets, who are in the adjacent pen, started laying.) Needless to say, the girls are not impressed.
T.S. and I, on the other hand, are impressed. Notice how they make the feathers around their head go out and how they puff up their whole body. I'm assuming this is to appear larger. I googled "why roosters fight" and mainly came up with real rooster fights. I also found some male enhancement products, but we won't go there.
Here are some pictures to show how the fight goes. Usually they bow down to each other, fluff feathers, then jump at/on each other. Then the whole process starts again. The hens continue to go about their business scratching and pecking like nothing is going on.