lol, for some reason I have noticed with my bantam roosters, they are either the sweetest, best, most amazing roosters, or they are little turds. I always like to say they have "little man syndrome". I have noticed for sure that when they are going thru "puberty" they can be very aggressive and quite amorous with the ladies breeding them half to death. I had some that were doing the same thing as yours and I threw them in a "bachelor pad" for a few months until their hormones leveled out. They are fine now. it could be also that he is trying to establish his place in the pecking order (which for the rooster usually tends to be at the top unless you have some really stubborn hens or he is timid). I would give him a little time, as personally, I think a somewhat aggressive rooster is better at protecting his flock. But if he turns into a turd that flogs you all the time or is always being mean to everyone, it would be time to find him a new home, either in the freezer or with someone else.