Officer Lopez: Attention! Attention! Ladies and gentlemen, attention! There is a herd of killer rabbits headed this way and we desperately need your help!From Wikipedia:
Night of the Lepus is a 1972 B-movie horror film in which giant mutant rabbits terrorize the Southwestern United States. The film was directed by William F. Claxton, written by Don Holliday and Gene R. Kearney, and starred Stuart Whitman as the main character, as well as Janet Leigh, Rory Calhoun, and DeForest Kelley, best known for his performance as Dr. Leonard McCoy on Star Trek. It was adapted from the novel The Year of the Angry Rabbit written by Russell Braddon.
Rancher Cole Hillman is having problems with the rabbit population on his ranch, who are destroying his crops. College president Elgin Clark, as a favor to benefactor Cole, calls in zoologists Roy and Gerry Bennett, who create an (untested) serum for disrupting the breeding cycle of rabbits. However, their daughter Amanda has become attached to the uninjected rabbit that has become the serum's test subject, and switches it with an already-injected bunny. The injected rabbit gets away and breeds. The serum doesn't disrupt their breeding cycle, but does something worse: it causes the rabbits to become gigantic meat-eaters. When several people are slaughtered by the carnivorous carrot-munchers, Roy and Gerry attempt to find a solution before the whole of the American Southwest is overrun by giant rabbits.