Disney made a small mistake with The Fox and the Hound. The idea sounds good on paper: star-crossed friends from opposite sides of life learning each other’s role in the world.
But in reality, the original story upon which the film was based is absurdly dark. The novel of the same name features Tod having children, who are both killed early in the story to spark Tod’s anger towards Copper and the hunter. Tod kills The Old Chief on purpose (rather than accidentally injured, as in the film) and Copper chases him until he dies from exhaustion. Not to be satisfied with this as an ending, Copper is then shot by his master.
The Disney version softens up the story quite a bit. But Tod and Copper still turn against each other and, even at the end of the film, they learn that they are naturally enemies never to reconcile. The moral of the story remains that some people may feel like they can be friends, but the simple way of the world will prevent it.