Train your chickens to come when called, so you can let them out and get them in anytime you want. Also enables you to call them to safety when predators lurk. If you have multiple flocks, you can train each to come to a different call. Very helpful when you have new pullets free ranging with old flock, and need to get each flock to its own coop.
The idea of true free range chickens is great, but in reality it's dangerous. To balance freedom and safety, we use a modified free range system which we describe in detail, along with tips on fencing, layout and location of chicken yard, providing cover, choosing appropriate chicken breeds, etc., so that you can develop your own limited free range system.