I've had several flocks of all pullets that I raised from chicks. Without exception, there was always some posturing and play fighting with the little ones as they began to grow. It's a simple establishing of the pecking order. As long as they aren't hurting each other, let them work it out.
If they should happen to be roosters, you will need to add more hens or get rid of one of them as 9 hens would not be enough for two roosters.
I have two roosters with 32 hens. They don't fight each other at all and run around together, in fact, since they were raised together. They both mate the hens and manage the flock - the one with the cushion comb is the dominant one, and the one with the straight comb is the junior rooster. He follows the senior guy around and when he mates a hen, the junior guy tries to jump on too! It's funny to watch because the hen usually runs away from both of them. I'm waiting for the senior guy to whip up on the junior guy for doing that, but it hasn't happened yet. They're still young - they were hatched in July of this year. They are white leghorn/buff laced polish crosses.
