My chickens started free ranging at about 7 or 8 weeks. I let them out for the day, they come back to the tractor at dusk. They don't go far from shelter, so haven't gone past the house on the one side, or more than 50' past the tractor on the other side.
They have lots of places to hide in between, such as under either of the decks, under the vehicles (2 trucks, a boat, a quad, and a car), under the carport, etc. They seem to stay close to these areas, and prefer the area where the rose bushes are planted.
I have dogs to ward off ground predators, and the wild birds do a good job of warning when the local hawk is around. The roo's protect the hens, and it seems to work very well after the hawk actually got one of the hens!
The blue jays warn me about hawks as well, and if I hear them squawking, I head outside. So far, so good. Now if I could just figure out what is eating my lettuce sprouts....(not the chickens, they won't stray that far)