As a bit of trivia, in 1999 (I believe), the AKC voted to recognize the breed as an official AKC breed and the name was changed from the
Jack Russell Terrier to the Parson Russell Terrier. Why, I have no idea, I just know that it was changed. :)
How much are you feeding your guy? Does he get exercise on a daily basis or is he a couch potato? JRTs (I know, I know, but even with the name change, old habits die hard! LOL!) are FAMOUS for being wonder agility dogs.