Sir John Hurt spent so long waiting around for something to do that he made The Elephant Man (1980), then came back to shoot more scenes for this movie.
This movie is notorious for the amount of animal abuse that took place during production, including real cockfights and decapitated chickens. Horses were tortured, and at least four died. The outcry prompted the Screen Actors Guild and the Alliance of Motion Picture & Television Producers to contractually authorize the American Humane Society to monitor the use of all animals in all filmed media.
Wondering why they were paying so much to rent the land where they were filming, United Artists checked local records. The owner turned out to be writer and director Michael Cimino.
Tom Noonan called this movie one of the worst experiences of his life. He claimed that Michael Cimino abused the actors, actresses, and the crew, including holding a loaded gun to Noonan's head during a dispute.
Willem Dafoe, in his feature film debut, appears briefly as a cockfighter. According to Dafoe, his role was supposed to be much larger, but during a long lighting set-up, he laughed out loud at a joke an extra told him. Michael Cimino was so annoyed that he fired Dafoe, and he is uncredited in the final cut. He later narrated Final Cut: The Making and Unmaking of Heaven's Gate (2004).