The Yorkshire terrier breed began in Great Britain. Originally called a "broken-haired Scotch Terrier," the breed was renamed the Yorkshire terrier in 1870. They came to the United States that decade and the American Kennel Club (AKC) admitted them as part of the toy group in 1885. In 2009, Yorkshire Terriers had the third highest number of AKC registrations.
Both the Kennel Club in the United Kingdom and the American Kennel Club recognize only one breed name for Yorkshire terriers. The breed, unlike some others, does not have a size division. Therefore, in registration, the only breed is Yorkshire terrier. Originally, the AKC split show classes according to size, less than five pounds or over five pounds. However, the standard was determined to be between three to seven pounds with all dogs eventually shown together.
Because the Yorkshire terrier is part of the toy group with AKC, all registered Yorkshire terriers are toys. Breeds in the toy group are all small and typically under 15 pounds. Most breed clubs, including Canada and the United Kingdom, place the Yorkshire in their toy groups.
No national breed club recognizes the term "teacup." Teacup is a term used in advertising dogs that are smaller than the breed standard. Since the breed standard for a Yorkshire terrier is a minimum of three pounds for adult dogs, a teacup would be a Yorkshire that is less than three pounds when grown.
A responsible Yorkshire terrier breeder seeks to produce dogs that are standard size. Code of ethics guidelines prohibit breeders from labeling their dogs as teacup, micro or any other size, according to Gale Thompson, Yorkshire Terrier Club of America. Very small Yorkshire dogs frequently have genetic and health problems, according to Thompson. Breeding runts is a common way to produce teacup dogs, according to Vet Confidential writer Louise Murray, who has a doctorate in veterinary medicine, and received a diploma from the American College of Veterinary Internal Medicine.
Some health issues of teacup dogs include whelping problems, low blood sugar, liver shunts, dental problems, fragile bones and other orthopedic issues, according to Murray. According to Joe Geller, a writer for DogChannel who also has a doctorate in veterinary medicine, congenital abnormalities and other issues may cause runts or teacup dogs to have special needs.
Yorkshire terriers from responsible breeds may be as small as three pounds. Breeders who concentrate on healthy size, instead of marketing concept, work to produce a pet that may live longer with fewer medical issues. The difference between a three- to seven-pound Yorkshire terrier and one that is less than three pounds can be the life span of the dog and extreme medical bills for the owner.