My Dog Shep (movie, 1946)

An orphan boy on his way to live with his uncle picks up a stray dog, and the two become fast friends. However, the uncle doesn't want the dog, and when chickens are found dead, the uncle accuses the dog of killing them. The boy decides that it's time he and the dog hit the road so they run away, and meet up with an elderly man who also ran away from a home where he believed he wasn't wanted either.