You should call the animal control dept on this guy. Sounds like he needs to have things explained to him.
If they don't do anything about it, and if the dog keeps coming around and you don't want to kill it, then shoot it in the butt with a shotgun from about 30 yards away with some #8 birdshot. It will have to be taken to the vet, and hundreds of dollars spent, to have all those little pellets removed. The owner still may not care about your chickens, but he will then understand that keeping his dog home is in his own best interests.
If they don't do anything about it, and if the dog keeps coming around and you don't want to kill it, then shoot it in the butt with a shotgun from about 30 yards away with some #8 birdshot. It will have to be taken to the vet, and hundreds of dollars spent, to have all those little pellets removed. The owner still may not care about your chickens, but he will then understand that keeping his dog home is in his own best interests.