Wow, the original novel was DARK
https://en.wikipedia.org/wiki/The_Fox_and_the_Hound_(novel)
Funny also how little the film (even aside from general tone) has to do with the story of the book; in the novel Tod and Copper NEVER become friends but are enemies beginning to end, whereas in the movie their friendship is central to the story. About the only things the film seems to have kept from the book is the name of the story and some of the characters.