"A teacher brought in a rabbit, and did a demonstration about how a rabbit would be prepared as food for a family," Nampa School District spokeswoman Allison Westfall said, according to KTVB.
Westfall added that the demonstration was not part of the biology curriculum.
The teacher put the rabbit into a restraining device before snapping its neck, KTVB reported, citing Westfall.
Students were reportedly warned about the demonstration and given a chance to leave the room.
Still, some who stayed were disturbed by the killing and some parents called later to express their displeasure.
The teacher, whose name has not been released, is now facing disciplinary action, the report said. The school district did not elaborate about whether the educator had been suspended.