I kept mine penned in a 12' x 32' run for a while. The first couple of times I mowed they ran into the coop, did not like that mower at all. Then they noticed that when I mowed by the run, bits of grass was thrown through the fence inti the run. After that, when they heard the sound of the mower they ran to the run fence to wait on the grass bits.
I did free range them for a while. They stayed away from the mower. They could get their own grass bits.
I did free range them for a while. They stayed away from the mower. They could get their own grass bits.