Although Tod was Demoted to Extra in the second film and Copper was shown to shine in the film, if you think about who was the protagonist and the most important character in the first film, you'll realize that the focus merely switched over from Tod to Copper.
The Fox and the Hound begins with the baby fox's mother hiding him and sacrificing her own life for his, Bambi-style. However, foxes almost never have a single cub. This mother wasn't just carrying her baby to safety. She was carrying to safety the only baby of the litter who survived the hunt.