We began free ranging only after our flock had established attachment to their coop and 20 x 20 outdoor play area, fenced with 4' chain link. We trimmed a couple of hens' wing feathers, those who seemed determined to "escape." After several weeks of learning what "home" is, the hens were released for their 2-3 hour free range time. We always leave the run gate open so the hens can return when they want to lay eggs in nest boxes in the coop or want water/feed. Some consistently return early; one always wants first dibs on the night's roost. A few will stay out til we have to herd them home, as if they can't scratch enough under the pines or devour enough garden chard. To your question, we have three acres, borders not fenced. The hens always stay within sight of their home yard. They've learned to meander around our house, but always stay close by it and return to their back yard view of their home coop. I was amazed at first, but now I'm comfortable and trust their sense about "territory." ~G