What does everyone have as ground cover in their duck pen? Currently I have dirt.... aka MUD..... and am thinking of going to pea gravel. What is the best for ducks and their feet? I need something that drains since I am in Oregon and it rains and rains and rains. I can't get the ducks in a dry enough area and am thinking if at least the ground is dry-ish it would be beneficial. The ducks are constantly dirty and I want them to be able to clean off.