Hello there and welcome to BYC!
Did you introduce these birds slowly, or just throw them together? It is best to intro them slowly from behind a cage or fenced off area for a few weeks so they can get to know each other with out too much blood shed. But as long as they are not killing each other, you can leave them together. However because there is a pecking order, there will always be one that is dominant toward the others and more so toward new comers.
So you will need to add more feeders and waterers so the new birds don't have to compete for food or water. Lower ranking birds have been known to starve to death because they can't get to the feeders. I just added some young chicks to my flock and added 2 more water and feed stations as until they grow, there will be competition.
As for roosting, you may need to go up at roosting time and get the newbies up on the bar at the other end by them selves for a while, til everyone learns their spots. Chickens can be brutal.
If this more dominant hen becomes completely impossible to deal with, you can try rehoming her or use pinless peepers on her. I have a very dominant hen that was a comb ripper when she was young and was brutal on the other hens. So she had her time in the pinless peepers for a few years. She has since calmed down enough that she does not need them anymore.
Good luck and it is really up to you to make sure these new birds get their share of food, water and roosting space. You may need to put in another bar.