Being raised together has almost no influence on how chickens get along. Space is probably the most important issue. Often times what was more than enough space for chicks, is not enough space for full grown birds.
And how that space is used is also important. Are there roosts in the run? Platforms, hideouts? You want to add more clutter, which will let the birds use the third dimension, height. Things in the run that let birds get underneath or on top of actually gives them more usable space, and lets them get out of sight of each other.
Mrs K