A buddy of mine who has taken the time to teach me how to hunt this year had almost the same problem. When he and the guy he was hunting with got out of his truck, he had a rott. and some kind of mixed breed dog come running at him. The dog was nipping at his pants leg and my friend had nothing in his hand to defend himself. His friend ended up hitting the dog with the butt of his gun a couple times and the dogs ran off. He went to the house of the people who own the dogs and told the owner that he would shoot them next time if it happens again. The thing about this was that my friend and the owner of the dogs are sorta friends. I guess the owner got the idea and has kept the dogs locked up. As for my friend he bought a can of pepper spray to keep on him in case it happened again. I believe my friend would have shot as well. If this guy wants to sue then I would counter sue for the dog bite like many others have said. It sounds like the dog owner has no respect for his dog to allow it to be put in that situation.