I currently have a small flock (rebuilding flock after being out of state for 3 years - wife's college) that's around 6 weeks old that have been in the new coop. We're a bit cooler here in VA than you are - temps have been down to around 36 degrees and as high as 80 degrees - staying in the 60/40 range for the most part the past couple of weeks. On the significantly cooler nights, they go inside their huddle box (which is essentially a 8' x 6.5' coop within the main coop/run - my coop is linked in my signature to get a visual) and roost inside, but on nights where it's not really cold - they stay in the run - either perched on one of the perch options, or sometimes (more rarely - usually when raining or such) they'll all congregate and huddle underneath the huddle coop. If your run is secure, I don't see an issue with them bunking under the stars. I think security and ventilation are probably the most important factors in keeping a flock healthy and happy.
My coop is in a clutch of maple trees that keeps them shaded and offers some protection vs. rain. I added solid back and front walls to my hoop coop to protect vs. wind - the wind blows against the back plywood wall on my land and the rear half of the coop is covered with a trucker's tarp (on top of cattle panels + hardware cloth). The upper side of the coop rests on tangled, rooted, rocky ground that I couldn't dig into with picks, shovels, etc. It levels out on cement blocks that are buried or partially buried (I'm adding some soil and wood chips to finish off the cement blocks soon) and I'd buried a segment of metal fencing about 10-12" around the entire base of the coop. I plan on planting some cover crop there to 1.) make it look better & 2.) discourage digging predators and make it easier to detect digging attempts. I feel comfortable in my security, while recognizing there's always a chance something happens - I give my coop a quick inspection daily when I go to check food/water/well-being. All that to say this - I'd make the coop as secure as you can, and let your birds have the run of the place. You'd need a covered run if you don't have one to keep out climbers and birds of prey, but I like that my birds have access to open air and more square footage 24/7.
Edited by 0wen - 5/21/16 at 1:51pm