You could buy a piece of that bamboo screening from home depot, cut it to fit into place on the back side of the run, it will help block the rain from coming in but still lets the air flow through.I wonder if I close off one side on the run with plywood or something similar and then make an over hang in other side? Gosh I just don't know. I agree petrel that the deep litter method would get as wet. What are thoughts on making the run larger so it's not so thin?