I think it's normal dog behavior. After Duke has a good potty, he'll scratch out with his back feet. It's really funny to watch. And when he gets back inside, he runs around the house a bit if it was a really good potty. Someone here once told me that it was party of marking their territory. I think they said there were some glands that produced smell between the toes. Can't remember but I do remember the phrase "frito feet"