Pure-bred Jack Russell Terrier

Junior a tri color Jack Russell terrier. He is only 1 year old right now weights in 14 pounds.I do not plan to breed him until he's 2 years old or older. I like to make sure he is mature and healthy enough to breed. He very intelligent and trained since he was a puppy. He listens off leash and loves to run in the woods chasing squirrels . His exercise regiment consist of 4 mile trail in woods which I bike and he runs off leash chasing whatever moves with my other Jack Russell and the dog park.