Hollywood, It's a Dog's Life (2004)

Hank O'Hara is a former stuntman turned dog and horse trainer. In the opening we see one of his dogs acting in a movie. Hank's widowed daughter and her daughter return to Hank's place, and the 11 year old granddaughter turns out to be a talented dog trainer. We follow Hank and his family, human as well as equine and canine, as the animals act in several movies and a commercial, and we meet many interesting personalities on the way. "Big Chuck" is the older, experienced dog, and "Little Chuck", also called "Junior", is the younger dog, just learning his job.