Dug 10 foot to a dog baying at fresh air, never dug a rabbit with one of my dogs but have with mates dogs, dug to a young dog digging up a tiny tube, lifted him out and two rats jumped out... , dug a young dog 16 times in his first season, including a few deep/long ones and never put a foot wrong, took him down country for a days digging on invite and he did 5 minutes in a one holer that was about a foot deep and wouldn't re-enter, so tried him at a different earth and same again, had been with the game both times before quitting cold, there's nothing stranger than terriers.