I don't know what he would be mixed with that wouldn't show more. The coat is all working sable to me. Tail is too short, but the hips and carry of the tail still say GSD to me. The legs are long, and the back legs are abnormally straight, but who knows how nutrition/sickness/or other factors of his environment have played into those things.Could be purebred, or if not very high mix. Legs area bit different but that really does not mean much, some lines have less angle to hock. I love his face. Thanks for taking him in and caring for him.
Not all GSDs have erect ears. Soft ears happen, as do injurred ears.A purebred GSD will have: large erect ears, medium set brown eyes, a long muzzle that's always black - except in white GSDs - and it will have a barrel-shaped body with proportionate legs. A high GSD mix should also have that rangy look. If the above characteristics aren't present, its definitely NOT a GSD!