I'm planning my first coop. I'd like to make it 8x12 to accommodate a large flock, which I hope someday to have. I'd also like to raise it about 12" from the ground so the chickens can get under it in the summer for shade (there will be other shade available). We're using 2x6"s for the floor joist, with 4x4s in cement deck piers. How often should there be a pier support for the joists? I'm drawing now with a pier every 4', but that seems awfully overengineered for a building that will just have chickens in it 99% of the time. Can I get away with every 6'? Thanks!