What state are you in? Are there hogs in your area? I saw where the Deer have dug around where we put corn down and the area has about 2" depth and clear hoof marks. Why it would be wet I can't answer though other than a heavy due weting it in the early part of the day. I don't know if hogs dig and then piss where they dig but I'm sure your would smell that if they did. When you figure it out let us know I'm curious about it.