He barks. And barks. And barks. The only thing that works is making him come inside....

My shepherds generally haven't been excessive barkers. I mean, they bark if there's something to bark at (like the darned dog that runs Up & down the road, trying to start fights thru the fence, and impregnating a neighbor's dog repeatedly) but nothing excessive. And if Sebastian barks, I know to go look because something is WRONG!!! All of the shepehrds who came before him were the same way....

Have you investigated one of those citronella collars that releases an unpleasant scent (at least to the dog) when they bark? Not to use forever but to train him with negative reinforcement?