When Detective Mandy looks out the window to investigate a noise, the film cuts to Night of the Living Dead (1968), the scene where the zombies are moving on the house, a nude female zombie walks across the shot and an older male zombie eats a bug.
The scene with the crows advancing on the two pig cops, ready to tear them apart is a direct spoof of the scene in "Night of the Living Dead" where the zombies advance on Duane Jones' character, Ben (you can tell from the slowness of the crows' moving in this scene that they're supposed to be acting like zombies).
