In the spring, I am getting bantams from Ideal. I plan on getting three, (Motled Japanese, OEGB, and Mille Fleur)( Hens). I have a large dog house that is unoccupied, and i was thinking about making it a coop. I would cut a small door with hinges in the back to get eggs, and attach a run to the front. How big should the run be for three 22 ounce bantams?