Shoot every damn one of them. Last fall my dog got into one every weekend for four weeks. First one I was able to pull them out, second time I had to bring him to the vet, third time I was again able to pull them out, and the last weekend he must have thought he was tough because he had quills all down his chest and legs and face. He had so many in his mouth that he couldn't shut it and had some in his eyes. By the time I got home he wouldn't let me near him and was growling at me. I had no choice but to put him down. So kill every porcupine you see.