We are putting in a new run closer to the house, the site is pretty level and currently grass. I don't want a dirt "floor", it will end up stinky mud. Sand, gravel, pebbles, concrete pad, etc, are all out, too, as I don't want to create so permanent of a scar on the land. I also will not have a rain-stopping roof (this year). The stocking density will be 10 sq ft per chick to start, moving down to 35 to 40 sq ft per bird as we expand the run and decrease the flock size (once we see how many roos are in the bunch). My idea is to lay pavers on the dirt (not bedded IN the dirt, but on top) "wall to wall" to keep the birds off the dirt, then to add 4 to 6 inches of wood chips over top of the pavers for them to poop and play in. Maybe a tub of dirt/sand in a corner for dust baths. My goals are happy birds, no stench, no mud, infrequent run cleaning, and being able to revert that chunk of land back to grass fairly easily if the chickens are moved again. Has anyone tried anything like this?