I'll usually free range when I reliably trained my chicks to come to me when I call them. I should say, when the shaking sound from the treat box calls them. That's what I'll usually do, with them still on a closed area I'll have a Tupperware with some scratch, give it a shake, call chick chick and give out some treat. you don't need to send out very much scratch at all, and you'll be shocked to see how quickly they pick it up. Soon the shaking sound/chick chick will be the most important sound in the whole world.