They are always out in the run. I swap out with clean waterers in the a.m. and add more food to the feeders. So they big birds had access to food and water, and the younger pullets had access in an area I blocked off with pallets so they could escape the bigger pullets.
They were in the run together with no apparent issues before I showed up. The birds all come running when I step into the run. They only other thing to mention is that the older birds all have been laying for a few weeks, and do their little mating dance when I step through the door. Then they turned on the littlest pullet.
There isn't a reason to resource guard. Maybe hormones?