Sparring is pretty common with both sexes, so as long as they aren't drawing blood I wouldn't worry about it... if they are really bad then I would just cull one early if you can't separate them. They will eventually start to go after the girls, but with any luck they will be ready to star in dinner before they get too bad... I like around 16-20 weeks for that kind of breed as dinner, but with roos any age they start to annoy you is a good age ....