Apr. 28, 1962 - CBS-TV, long faithful to “Lassie,” becomes a two-dog network next fall when “Rin Tin Tin” comes barking back each Saturday morning. CBS, incidentally, probably will exhibit more animals next season than any other network. In addition to Lassie and Rin Tin Tin, the menagerie will include Mr. Ed, the talking horse, and Alvin, a chipmunk. There is also a rodent, Mighty Mouse.