My husband and I have decided that all we need is a 3 sided coop open to the run for now. Where we live it gets in the 100s and stays there. Most of the time. Do you have to go by the same amount of square footage for an open design as you do for a totally enclosed one? The run area is just for when I'm out of town or something and want to keep them contained, and at night. Other than that they will free range. Nothing I have seen really addresses this.