All I know about tail docking is that it is suppose to be done if your going to show the dog and compete. YEs, it is the standard in full bred dogs .However, Not all Full bred dogs of any breed are going to be used for show. My Suzi is not , I am not conncerned with that. She is my service animal and she is a pure bred Yorkie. IF I was interested in have her as a show dog then YES, I would do what was required to have her meet the Breed Standard. I do not know why it included though, because it is not how the dog is born to look. BUT, they the standard has certain rules that must be followed. Even if it means alteration .
