We were fortunate when we moved in that the previous owners left a great 10 ft x 10 ft storage house under the next on a cement slab. We have gotten to work putting in ventilation, windows, roosts, and nesting boxes to transform it into a great coop! The difficulty we are having is deciding where to extend the outdoor run. Under the deck there is drainage rocks sloping away from the house. From all my research sand, hand, dirt etc are the main things used for the run. We originally planned on having the entire run jut out from the deck into the grass, but i was thinking we might be able to add 200ish sq ft if it is possible to use the space under the deck! Does anyone have experience with having the run covered in decent sized rocks/drainage rocks? I understand it would be more difficult to clean. Any input is welcome! Thank you in advance!