NATIONAL DOG SHOW PRESENTED BY PURINA — “The 12th Annual Nation Dog Show Presented by Purina” in Philadelphia, PA 2013 — Pictured: David Frei and John O’Hurley — (Photo by: Bill McCay/NBC) John O’Hurley and David Frei It’s a Dog Show Life by Jay S. Jacobs It has become a Thanksgiving tradition, just like turkey, cranberries and too many relatives.  The National Dog Show presented by Purina airs annually on the holiday, right after the Macy's Thanksgiving Day Parade.  After al