Much more ventilation. Increase the (loft) coop size, but you could maintain the same overall footprint. skirt around the cement blocks to keep diggers out. Be sure it has 2 x 4's laid on the flat for the perches. You can round over the top corners if you want. 1/2" hardware cloth everywhere to make it predator proof, including over the venting. Solid floor in the loft. No wire floor. During the winter, you can close in the run area with clear tarp or plastic to give them a green house if you are in a very cold area. But, if you do, of course, you'll have to leave a good part of it open for ventilation, and be very careful that it doesn't overheat when the outside temp goes up a bit and the sun is stronger. Good big clean out door in the loft. I'm sure you'll be MUCH happier with this design, and it lends it'self well to expansion... if you ever feel the need.