My run in Maryland was ~800 sq ft and only a quarter of it was covered. If you are doing deep litter, you WANT it to get wet occasionally - that supports

the breakdown of the material, just like in a compost bin. Make sure you don't have just one type of substrate. I would use pine shavings in the coops and clean those out directly into the run 2-3 times a year. In summer, grass clippings went on there, preferably after sitting out for a couple days but I did put them in fresh on occasion. In Fall, leaves, pine cones and pine needles went into the mix, and in winter I would add a bale of hay about every six weeks or more often if the ground was starting wet since it wouldn't dry out as fast in winter. In 4 years I never had to scoop out my run and no, it was not a stinky fly infested mess. If anything, it'll be the perfect garden for the new owners of they're so inclined.