PetSmart is letting the dogs out. The 1,450-unit retailer is collaborating with Illumination Entertainment and Universal Pictures on a marketing campaign around the upcoming film "The Secret Life of Pets," which will hit theatres on July 8. On Monday, the Phoenix-based chain plans to begin airing two 30-second animated TV spots. In the commercials, animals from the movie, which tells a story of what happens when pets are left to their own devices without human interaction, visit a PetSmart store. The film stars comedians Louis C.K., Ellie Kemper and Kevin Hart.