Ok, I'm getting started building tomorrow! making a lean to style coop for 5 hens. Live in northern california near san jose. I plan to have the floor of my coop made of wire- not solid wood so droppings go onto floor under the coop. Do I need vents bult in the coop if the floor isn't solid? My coop plans are 4 wide, 3 deep, 4 tall in back.