The dog is marking his turf, to make sure it's in a place where any threats to his position in the pecking order can pick up his scent. Obviously the dog doesn't realize that babies don't operate the same way other dogs do, but that's most likely what's going on. He's not sick, he's just letting the new arrival to the pack know that he's still got rank. But you
must ensure that the dog learns that, no.... he's been demoted and the baby ranks higher.
