Some breeds may be barkier than others. We always have 'pound pups' and are partial to lab/hound mixes (although our current princess looks to be a shepherd/hound mix.) I think bored dogs, dogs that don't get enough attention from their families, and fearful dogs are all more likely to be night barkers than other dogs. (I'd be bored too if someone left me out on a chain night and day, or closed up in the house with no company.) I also note that dogs behing those 'invisible' electric fences tend to be fierce barkers. My theory--they approach the boundaries when people walk by. They get shocked. They think people walking by shock them. That would make me angry and fearful too.