OK, so I have a protected nighttime pen for the two Ducks. It is a 5x7 Chain Link Dog Kennel with a roof. Attached on the side is a dog house for the ducks to sleep in. After putting the hardware cloth on the bottom to prevent predators from digging in, I am left with the decision of what would make the best flooring? I want ease of clean up, but also something that is not going to hurt the ducks feet. What do you all do?