Shows the power of friendship over the expectations and prejudices of others. There's also a line in a song, "from our sadness, happiness grew," showing that sorrow over loss and loneliness can be a window to new beginnings.
Tod is orphaned at the beginning of the movie when his mom runs dogs away from Tod and a gunshot sounds in a field. He's later abandoned in the forest by his human caretaker in hopes that it will save him from getting hunted. Amos is constantly shooting at Tod and seems obsessed with hunting gear -- his shed is full of traps and pelts, and he tries to use a trap on Tod and sets fire to Tod's burrow to fish him out. Chief the dog is hit by a train, falls off a trestle, and breaks his leg -- his eyes close in a stream and it looks like he's died. The fox and the hound have a ferocious fight with a bear ending in a fall off a waterfall cliff. Birds and a caterpillar get electrocuted.
Some flirting between foxes and Amos runs out his cabin door in his underwear.