Yup!! Just cuz he's a dog!!
Neither of mine roll in mud, but Sierra loooooooves anything that stinks!!
The stinkier the better!!
My parents have a creek out behind the house and it's pretty shallow and muddy all the time and their gsd/lab mix lays in the mud every chance she gets! I was just at their house the other day and it was cold (35 F) and she was covered in mud! She had just gone for a roll!!