almost always this behavior is due to insufficient space and overcrowding. As the birds grow, they need more space. Put up a pallet on bricks, put a roost in the run, or a tree branch, put a box in kitty corner. It helps to create mulitiple levels in the run, and hideout areas, where birds can get away from each other.
It seems counter intuitive, if you put stuff in there, it will make for less space, but it often gives more space, for example below the pallet and on top of the pallet, doubles that area.
It makes the space less boring, birds can jump up on things, down under things, around the corner. It can help a less aggressive bird get away from a more aggressive bird.
Mrs K