I wouldn't worry about the roosters fighting. They will do some of that till they have the 'pecking' order in place.
I would be (much) more worried though about the Rooster to Hen ratio.
I have about 75 hens and 6 roosters at the moment. Mine are about 4 1/2 months old so maybe they will calm down when they get older, but they are constantly trying to mate the poor hens.
I would swear that somehow the roosters know which hens are old enough to lay eggs. They at first were only trying to mate the Red Stars (which began laying several weeks ago). Now that the Black Stars are starting to lay, they are after them too. (But the hens like my RIR's that are NOT laying yet, are not chased/mated by the Roosters!).
On a side note, I always pictured Roosters in the same way as Song birds like cardinals. I figured the male would crow and otherwise try to 'entice' the females. Chickens (and I found out Geese/Ducks) are not like that! They will grab a poor hen completely without warning! I've had a lot of explaining about the 'birds and the bee's' to my kids the last couple of weeks!