Rainy day in Mississippi

We have 2 great pyrenees dogs. Supposed to be our livestock guardian dogs. At this point they are more interested in digging out of the area they are supposed to be guarding! Does anyone know more about how to keep these guys in. My husband is about to strangle them, although this would be impossible since they weigh almost as much as he does. The picture on the front page is of one of them this summer. They will be a year old in January. Today they are caked in mud. What's amazing though is after the rain stops and the mud dries up they go back to being pure white and beautiful.