The US standard actually penalizes an undocked tail, but length of dock is not specified. The average seems to be about 4" in show lines. The Australian/NZ standards state the tail should be no more than 2" long; of course in most (maybe all) of Australia the choice to dock has been taken away, but the standard has not been changed.
Acie's is just a short fat little stub! I haven't measured it but if I had to guess I'd say it's about 1 1/2- 2 inches long. It's sooo cute when he tries to wiggle it! Kinda just twitches around! :lol: