An apparatus (10) and a method for stunning an animal, such as a chicken or other domesticated fowl, prior to performing one or more other processing operations on the animal, wherein the length of a path that the animal travels during exposure to the stunning force is variable. Varying the length of the path allows for compensating for variations in the speed with which the animal is moved along the path. By varying the length of the path in proportion to the variation in the speed, the time during which the animal is exposed to the stunning force can be maintained substantially constant, thereby avoiding the undesirable effects of over- and underexposure.