We live in the suburbs in Southern California, and my run is predator proof, but I don't want to gamble. I can't imagine how anything could get into my run (which is attached to the coop) but I know that hungry predators (even in the suburbs) are determined, so even though I don't know how anything could get in the run (and therefore into the coop) I go out every evening, just at sunset and close up the coop. The girls are invariably roosting and very mellow, they don't make a peep all night.
Before I converted and joined the lock 'em up camp, I used to have this recurring fear that I'd wake up at 2:30 in the morning to the sound of terrified and dying hens, under attack in their coop by some nefarious nocturnal predator. Now I sleep well, because nothing is getting in that coop when it's locked up.
-Scott