We think our dog came from low-life's you describe...she's a sweetie from the pound 18 mo. ago, except when someone comes near our property line...she scares people (hair up, barking, very aggressive stance)....I was just reading about chained dogs having problems, and thinking that may have been her problem. We don't have a fenced yard, and a new neighbor, who has told us "She is afraid of dogs" is moving in....
anyone have any suggestions? She's 3, a lab/aussie? mix....mingles well with other dogs, and trainable, but acts so aggressive along our property....and we live in a neighborhood.