I live in a pretty urban/suburban area with little problems from predators. I frequently don't close up the the run till hours after dark. They free range unsupervised all day long while I'm at work.(In the winter long before light). The run is chainlink with a chainlink floor and cover. No popdoor. Fenced yard.
I guess I do everything wrong, but have only ever lost 1 chicken to a predator, and that happened at 3pm on a hot sunny summer day within feet of me and I never saw or heard anything. I think it helps that I have lots of trees, shrubs and a deck for them to hide under. Also the predators around here must be vegetarian. The raccoons will walk past the chickens to get to the cherries. The possums stopped living under the shed since I got chickens. and I have to protect the stray and feral cats from the hens. Neighbors dogs just ignore them. Now I don't come close to saying this is a good idea for most chicken owners, just works for me. All you have to do is read for a few minutes to see that protection from predators is a major problem. You'll need to decide for yourself what you can live with and what's best for your chickens. Good Luck.
Imp