I have no idea why you would pre-kill a pinky mouse of all things but I would imagine that if you destroyed it's head, it would be dead though you might get a little twitching in the limbs because of electric impulses.

On a side note, are you doing the "hit them in the head until they're stunned" method with all your feeders? I would highly recommened switching to CO2 euthenasia instead (I know it's almost impossible to kill pinks this way but there really is no reason to pre-kill pinks anyway). MUCH more humane.

This...kind of makes me sad to be quite honest... :/