I am going to be making several chicken houses over the next week or two and would like to know how big to make the door opening for them to go in and out of? Most houses will be 4x4x4 (4' wide, 4' long, 4' tall) with a few that will be 8x4x4. They are on pallets/skids so will be up off the ground about 6 inches (for air circulation) and when I put the roof on, it will have 1 inch thick pieces of wood at the corners so it has opening all around the roof for ventilation and will also put some holes in the side walls for ventilation/air flow. Of course those will be covered with screen wire to keep out nasty bugs and then that covered with hardware cloth for strength. I figure with all these houses scattered around the general chicken yard, they can choose and use what ones they want for shelter. I am not planning on a bunch of chickens living in each house, I know only about one or two is all that should be in them, but again, as I said these are for them to choose if they want to go into any of the houses. Each house will have it's back wall on hinges, so that the entire wall can be either lifted up or laid down (haven't decided which way to go on that one) to access the entire inside of the house. Also will have a 2x4 running the length of the inside for perching area. I am considering putting a couple nest boxes at the very back of the houses for choice of laying eggs, if any of the chickens want to use the house for that. It will be at the back at the wall that will either lift up or lay down to access the inside of the house.