Oh, I saw that coop in person.... There is NO ventilation in it! The only opening, besides a hinged side to gather eggs, is the floor hatch for hens to enter/exit. It is just a PVC box with one 9x9" square on the bottom open to the outside....and certain to be an oven when Summer kicks in. Can you say steamed chicken?
I mentioned that to the owner and she wasn't too pleased with my observation....kind of took the wind out of her innovation. HOWEVER, I'm sure if you're designing this easy-to-hose-out coop you could modify it to a more chicken-friendly design.