If you can provide power to your coop they can stay out there full time. I don't know what your overnight lows are but they may still need supplemental heat at night out there. My permanent brooder is in the coop, the chicks go out there straight from the incubator or the post office. During one heat wave I turned daytime heat off at 2 days and overnight heat off at 5 days. During winter I usually leave it on for five weeks. Your overnight lows will have a lot to do with when they no longer need heat. All they need is a warm spot to go to so they can warm up if they need it.
I've seen two week old chicks do some remarkable flying. You might want to make a wire or plastic mesh top on your brooder to keep them in. The ventilation up high is probably a good thing, I would not want to seal the top.