I have a "bolter," too. We just continue to work on it, and do not trust. The backyard fence is secure, and we don't let her near the front door unless we are holding her. Only on leash in the front yard, on walks, etc.
Do you have a nearby dog park? That would give your pup a chance to run "free," and use up a lot of energy.
__________________ Life is merrier with a Yorkshire Terrier! Jezebel  & Chuy  ... RIP: Barkley  Loosie  & Sassy  |