Your chickens will make things fairly easy for you. When they're young, they will be curious, step out of the run and in to the "real world", but won't stray too far from the access door. Mine would all get brave, run outside, scratch around, then run back inside....then repeat the cycle. That told me that they absolutely knew where "home" was. As each week went by, they became more brave, and stayed out longer, exploring new areas.
I have actually found that I don't have a set routine with letting them out, or keeping them confined. I work during the week, and my wife doesn't let them out to free range. When I come home, I try and wait until around 7:30pm to let them out, because they put themselves up by 8:30pm. On the weekends though, I usually let them out in the early mornings, and they usually stay out all day, under my dogs doghouse where it's complete shade during the searing heat.
To sum it up, your chickens won't run away forever like a dog or cat would. You won't need to post "lost chicken" signs anywhere.