My 8 week old chicks stay outside all day, when the sun starts going down they come back to the door and whine to be let in ( because currently I'm keeping them in a ferret cage in the house). They never stray too far though.
You could try supervised free ranging, my hens for some reason never go in the forest. If your chicks have been in the run for a while, at sundown they will come back, the only thing I would worry about would be the predators (and vultures don't kill chickens but they will eat a dead chicken).