Before you move them, can you feed along both sides of the fence, if they have a common fence line? Sometimes that can help.
Another trick that I think can help, is to have the birds either change places, or lock the old girls out of the run/coop, and let the young ones in the main set up. This allows the chicks to explore a new place to them, and it lets the older girls see them in this home place, without being pursued or chased.
Set up some hideouts, some extra feed bowls and set them up so that a bird eating at one station, cannot be seen from another station.
Chickens hate change, I know this sounds crazy, but another trick I do, when adding new birds, is I give a clean out, and I rearrange the hideouts, roosts, and shelters in the run. So that there is a lot of change to look at, seems to help.
Mrs K