I would go with the citranella collar before a shock collar. Shock collars can malfunction. You could also unplug or whatever it requires to make the doorbell not ring. I'm kinda at a loss for answers cause I like dogs to bark when someone is at the door. God forbid this ever happen, but what if someone is trying to break into your parents' house and Autum has now been trained or discrouraged from barking or has a shock collar on and won't bark. He could just try telling her to hush in a loud dominating tone when she starts barking.