Just keep in mind, since they will most likely live their entire lives inside the coop/run, don't skimp on the minimum guidelines for sizes. For permanently contained birds, I would not go less than 10 sq. ft. per bird of run space. So with four birds, you'd want a 5 x 8 or 4 x 10 or whatever. Obviously more space is always better. And that's for LF chickens, not bantams. My bantam coop is basically 4 x 10 (maybe just a tad larger), and I think it took about 3/4 scoop of sand to fill it with about 3.5 inches of sand. Of course you will have to deal with lugging it by the bucketloads up to the roof...lol.