What are the chances introducing a second dog will help him mellow out?
A neighbour has to leave town, and they don't want their one dog anymore. She is a 2 yr old tea cup chihuahua - jack russel mix. I am dead set against having yet another animal (2 cats, plus crazy dog already). I don't see how this would help the situation at all. She is very calm, submissive, doesn't bark much, and is pretty much the same size. NOT FIXED.
As for when the behavior started - pretty much once he reached his full size. I try to treat him like a dog, my wife and daughter try to treat him like another child.