I shoveled out everything. Put Mason's sand down almost an inch thick. Rake it until it's even, then put down a smattering of Pine Shavings on top. I had a 1/4 of a bale or so left, so I reached inside for a handful to scatter around and saw a Mouse inside. Then another. I was able to dispatch one of them, but the other escaped and finally ran out the "Human Door", with two chickens in hot pursuit! I dumped the bag onto the floor. Three baby Mice fell out, and were instantly eaten by my Chickens! Yuck! I didn't know whether or not to eat the eggs from that day or not! The Dog ate most of those eggs over a period of a week! But I suppose no worse than God knows what they find to eat when free ranging! Mice can not get in through the Chicken Door because there is no ramp. The Chickens have to "Hop" from two large wooden blocks about 8'' apart to prevent mice from entering. Their door is 12'' off the ground. The mice must have come in through the "Human Door" when I left it open one sunny day. My building sits on a large old Concrete Silo Base. It has a layer of concrete filled, concrete blocks on top with which the wooden structure is built, so it is Mouse-Proof. I will not leave the big door open anymore. But a simple "Chicken safe" mousetrap is a small cardboard box with a hole in the side of one end with a glue trap inside. I sometimes put a "Dollop" of P-Nut Butter in the middle of the glue. I caught two mice the next day. They like to crawl into small spaces along any wall, and this really works. Just dispose of it it the trash and you're done with them. Like I said, it is Chicken Safe. No Poison, no open traps, no mess. And No Mice!