There is a lot I don't know about your specific situation so it's a little difficult to get too specific about what you should do. I sometimes, but not always, have problems with mature hens picking on juveniles on the roosts. It's usually a mature hen that is at the bottom of the adult pecking order that goes out of her way to be brutal to the younger ones when it does happen. There have been a few times that the juveniles actually tried to roost somewhere other than the roosts.
I cannot guarantee what will happen with yours. If you have the room in the coop, it won't hurt to put up another roost. I always believe the more room the better with chickens. They may or may not use it.