The sheep story reminds me of a book I read years ago, drawn in by the title, "Bumble, Pig in Paradise," about a 300 lb porker, raised by hand from 1 lb piglet...still living in owner's farm house. Thoroughly housebroken (tho hard on the furniture) and leash trained. One would think a 300 lb pig could pretty much go wherever he wanted, leash or no leash, but apparently he heeled well. Pigs are very intelligent creatures...I suspect he wasn't about to blow Paradise for the thrill of a little tug on the leash.