The run that attaches to the side of the coop allows the girls to walk around if we are not home and need them to be safe/protected from predators. The whole run is covered in chicken wire or hardware cloth and the roof we quickly upgraded to clear PVC panels (you can see that a few pictures down). I made a screened human-size door to easily enter the run.
I added 2 vents to the coop and the windows are also open and covered with hardware cloth so that there is enough air flow and ventilation inside the coop. Even in the Summer (we live in Florida so it is HOT), the coop stays cool from the ventilation, shade of nearby pine trees and the cedar shingle roof).
Here's the clear PVC panel roof to the run that I mentioned above. It allows the girls to stay in the run even if it's raining outside. You can also see the cedar shingles on the main coop.
They walk up this cute little ladder to get into the coop at bedtime.
I added a hinged access door on the bottom of the run so that we can easily add food and water (without having to crawl through the run and under the coop). The silver bucket is the feeder and the home depot bucket has nipples underneath that I ordered on amazon and attached to the bottom. This is the cleanest/most hygienic way for the chickens to access fresh water.
I covered the bottom of the coop floor with cheap peel-and-stick tiles and painted the inside of the coop with floor paint so that everything could be hosed down if needed.