Tail docking is not something that was or should ever be done to APBTs or ABs (American Bulldogs). It was never a part of the standard nor does it serve any purpose whatsoever with either breed. As for when it should be done, between 3 and 5 days of age (with 5 days old really pushing it IMO). Should it be done for medical reasons, it is considered a major surgery in which the dog goes under general anesthesia.