Trivia

The house featured in the beginning of the film is the same used in Las siete puertas del infierno (1981) (aka '7 Doors of Death').

Just like "After Death" (1989) a.k.a "Zombie 4", which has no connection with its predecessor, "Killing Birds" (which has no connection to "Zombie 3" or "Zombie 4") was released as "Zombie 5" in various countries only to capitalize on the success of "Zombie 3" (1987).

Although the direction is credited to Claudio Lattanzi, various sources claim that Joe D'Amato, the movie's producer and cinematographer, was the one who actually directed the movie.