I live in Oregon near the coast. I went on vacation for a couple of weeks and while I was gone the lovely rain finally showed up. The run was nothing but mud when I returned. Here is my 4x10 tractor for my nine hens and roo. You can have a look, so I don't have to go into great detail describing the situation. I went and bought corrugated clear plastic roofing from the local hardware store and put it around the run. Like usual, they didn't carry exactly what I wanted. I had to go with the 28" instead of the 30-something. So, now the bottom 4-5" can still get rain blown into it, but I thought leaving that open might be okay, ventilation wise. Or, should I close up the bottom few inches also? What do you use in your run? If you don't live where it rains much, but want to give your thoughts, go ahead. Basically where I live, it will rain at least 20 days of the month until May. We get high winds (hence the tie downs on the coop). Each winter we see two or three storms with 100 mph winds and 12+ inches of rain fall, flooding, no power, etc. Basically "Sandy" is a normal thing for us here. Anyway, I've read sand, straw, woodchips, etc. But, what works best for rain? There's no way I'm going to use pine shavings. They would be wet within an hour or so. Oh, I suppose I should add this info as well. When we get rain that doesn't stop for at least 36 hours (which is often in winter/spring) the yard can't keep up and water basically just sits on top of the entire property and it sounds like a sponge when you walk on it. So, my thoughts are that the ground inside the run will eventually absorb water from the ground outside of the run as well. Here is a photo to show an example: There's no standing water like this inside the run, but you know the ground in the run is absorbing it, so that's partial to why it's still muddy in there after I put the plastic around the run. I live near a river and in the summer I use sand in the coop. I let it dry out first. For fall, winter and spring I am doing the Deep Litter Method inside the coop though. Should I build up the run floor a bit with river sand and then put straw on top of the sand and change out the straw? How long will straw last before needing to change it? Also, the next ten days is pretty much all rain, so the river sand will be wet and have no time to dry before going in. Is wet sand better than mud at least? Rain is such a pain. The chickens seem to not mind it that much (surprised me). If it's raining hard they run back to the coop if I've let them out, but light to moderate rain they don't seem to mind running around in.