https://letterboxd.com/film/the-slaughterhouse-killer/

In rural Australia a big nasty fucker named Box lives alone in shack and works in a slaughterhouse. You can tell early on that something is not right about this guy when he picks up some medication at the drugstore. At work a new guy named Nathan just out of prison shows up and Box has to show him the ropes. Before long they are partners in killing, sort of like Henry and Otis in Henry: Portrait of a Serial Killer.