I'd say usage of blunt force has through history mainly served to render the animal unconscious, the final clinical death often occurring only with the drawing of blood from the animal. Which is impossible to survive, unlike repeated hits on the skull. Even today it seems blunt force isn't considered a reliable method for killing an animal. Notably for animal that is being etuhanized (no processing after death) you essentially need to use either a firearm or a penetrating captive-bolt gun, since ethical slaughter doesn't involve repeatedly smashing the animal's head (WTF Bert? were you a kid or something?).