Breeders who let their Yorkie puppies go before 12 weeks of age are doing them a GREAT disservice! Sure they may be able to eat puppy food, may be able to live but they are NOT going to be as well adjusted socially and emotionally. The mother dog and sibling interactions teach puppies a great deal. They learn bite inhibition, they learn to play correctly, they learn the basics of housetraining, they learn self confidence and learn not to be so afraid of things -- they learn so much! You can also tell a lot more about your puppy by 12 weeks -- things like their ear set, their temperment, their potential size.....
Don't just take individual word for this. Our Parent Breed Club is the Yorkshire Terrier Club of America YTCA -- here is what they have to say: "If you are seeking a family pet a reputable Yorkshire Terrier Breeder will not release a puppy to a new home before it is twelve (12) weeks old. This ensures the puppy is old enough to have had some of its shots, has been checked by a veterinarian, and a health certificate issued. The puppy’s ears should be erect, and you can generally tell what size the puppy will be at maturity when it is twelve weeks old by doubling the weight. Although not a definite rule it is generally thought that if a twelve week old Yorkie puppy is three pounds it will likely be six pounds at maturity. Also, by twelve weeks the puppy should be outgoing and well socialized so it will easily accept the transition of leaving its mother and siblings. "
YTCA also addresses this issue in their Code of Conduct: "All puppies leaving the breeders possession will be a minimum of twelve (12) weeks of age to facilitate adequate socialization as well as appropriate emotional and temperament development through interaction with siblings, dam and other dogs. "
http://www.ytca.org/ethics2.html
Believe me -- spend a few years reading these boards and the problems that come to light when puppies are taken home before 12 weeks old are so telling! Time after time, we advise prospective buyers NOT to take home a pup until at LEAST 12 weeks old and time after time, they decide to ignore the advice because some breeder says it is okay. Sure there are plenty of unscrupulous breeders who want to sell them that early -- saves them the work, the puppy food, the shots, the care, etc..... The way I looked at it though, there was no way I was going to let my puppies go before 12 weeks. I owed it to them to give them the very best start possibly and that IS NOT DONE in 9 weeks.