No, it is not. Just hang in there and keep trying different diversions.This integrating babies is not for the faint of heart.
I see a stack of pallets in the background, those might work better than the pieces of plywood.
An chance you can let the littles have the run of the run(haha) without the older birds in there?
It will help them get used to the lay of the land without being harassed.
Grab some big old branches too.Go back in your woods tomorrow and rake some stuff up, to put in your run. This will give your chickens something to do, besides chase the little ones. I can't tell if your run is some sand or it's just dirt, but deep litter in your run would work well.