Well that's true, but you will probably want to have some at the top. You could drill like 2 inch holes (covered with hardware cloth) at the top. Top ventilation is really important, if not the most. Of course, all up to you! You have all summer (go in there during hot and muggy days to make sure it's not too bad), fall, and winter to figure it out.

My chickens are idiots, to be honest. When it's hot, sometimes I catch them in the coop, panting and holding out their wings. Never really understand why they do that, it's kinda still air in there. I think I'll have to add more ventilation also.