I have a fenced yard. I don't worry about predators because I live in the suburbs (no racoons or foxes, only crows that will pick off chicks, but are harmless to adult hens). Instead of a proper run (enclosure with a top on it) I just fenced off a corner of my yard. The only reason I even fenced off the corner of the yard is to make sure the hens would use the coop and lay their eggs where I could FIND them. My yard has lots of good nesting spots (including a crawl space under the house and under an old junky car) and in fact, once my hens were too old to lay, I let them loose in the back yard and they totally stopped using the coop and just slept under the house at night. Now that I have new chicks, I fenced off the corner of the yard again to make sure they use the coop just so that I can gather the eggs. If you don't have the chickens contained somewhat, there's no guarentee they will return to the coop at night if there are equally comfy spots in their range to hole up for the night.