I just completed the new addition to our older coop. The original was enough for 20, but we now have over 50. The new one has a single level perch, which the ladies love, to prevent politics in the coop, they have about 23 feet of perch space, in the new addition. I am experimenting with the sand versus wood chip cover for the poop trays. The lighting was found at the Restore. I selected back silver bar because of the ceramic sockets, for the winter heat lamps. We are in central Montana and see -38 at our home. It is fully insulated. The entire project cost under $3000, and is open to the older coop. We have 20 acres of field for the "run" so they dont have an enclosed wire space. They have numerous hiding locations for the wind and weather, however, there is enough space for several days of inside living , if needed