That's a great question as I've seen chips mold in other areas of my property but not in the Run because they are always stirring them up, scratching. Hay and straw molds and smells as it's composting so take it from me because I layed a nice path of hay for myself one year and regretted it, don't add that. It's only good the 1st day you lay it down and it's a rare dry day. After that it's horrible and you wind up having to rake it up and toss it in the compost. Wood chips have truly been the best as a 2nd runner up to excellent drainage.... For wrapping the run, I don't do it. But my Run is surrounded by woods - trees, brush, etc. so I don't have any issues with wind. It's also huge, about 1000sq ft. and they don't stay in it much. But I was thinking that if I had a typical, smaller run and if it's not very protected from wind, then wrapping a side might be nice to keep it dry. I'd wrap whatever side is not somewhat protected and gets winds that come down from the Cascades. I'd leave my southern facing side open for sunlight....
