All the Little Animals is a film from 1998 starring John Hurt & Christian Bale

Bobby (Christian Bale) runs away and meets a strange old man (John Hurt) who wanders the highways burying roadkill animals. Bobby becomes the old man's apprentice after running away from home. and learns to see the world of nature in a strange idyllic way. But soon the shadow of his stepfather catches up to him and Bobby's world explodes into a grotesque nightmare.

Quite a moving film really