Contrary chickens

I have 2 separate coops and runs, one for the older girls, one for the 9wk old chicks. Most of the day they are loose in the garden together, (they warily keep to their own groups). But they they do insist on going into the other group's run and eating the pellets. So my chicks are eating layers and my laying hens are eating growers! I want them to be able to eat whenever they want so don't want to pick the dishes up or lock them in their runs. The grass, (or in this case pellets), are obviously greener on the other side.

When I bought my first chooks, the breeder was throwing windfall apples to his big run of POLs causing mass hysteria, meanwhile one was breaking her neck trying get something else through the wire.

He looked at her and said - that's chickens right enough.  Always want the thing they can't have