Skunks are after the bees. They scratch the front of the hive and when the guards come out to investigate, the skunks grab them and eat them. Their coat is too thick to be stung through. If you raise a hive up enough so that the skunks have to stand on their back feet, it exposes their underbelly, and the bees can get at that!. That's all you usually have to do to dissuade them.