I did a search on this, but didn't come up with anything, so I'm not sure if you've already covered this subject. It's about what are called "teacup" Yorkshire Terriers. This dog is not an exotic pet, but some breeders have tried to make it that by mating the "runts" of litters to create these terribly small dogs.
Many of them only reach an adult weight of only 2 or 3 lbs. and this is unhealthy for the animal, and creates all kinds of problems. Not the least of which is that often fall prey to larger animals and are an easy target for hunting birds as well.
I got a Yorkie last Christmas, a standard one, and in the books I have about this breed it says that many vets and breeders alike are warning people about buying this "teacup" yorkie. There is no such sub-breed, and this is just being used as a way to put outrageous prices on these tiny animals. One of my books says there is a growing movement aiming to outlaw forcing these dogs to be so tiny.
I've been telling people I know about this since I got my little dog - who, at 7.5 lbs is already small enough!
Nancy Welker BellaOnline Yoga Editor