I'm going to say this because holding it in gives me a stomach ache. I am all for ethical breeders but I have a huge issue with mini or "teacup". Namely that there is NO SUCH THING. There are small dogs bred to small dogs or runts bred to produce small dogs who may or may not be healthy because of their size or poor genetics. Check the problems with teacup breeding to see what happens when you breed too small. And yet people still are breeding and selling. Good cocker breeders breed to meet breed standard and produce sound, healthy dogs. I'd not fall for the "small cocker needs a home line." Bad breeders breed to feed on the popular trend and the money it brings, i.e. miniature dogs. Buying more dogs from them just gives them more space to breed. If it's a matter of size then get a dog that's naturally a different size.
Because they're so tiny, these dogs have fragile bones that can easily break. It's easy to step or sit on one. A responsible owner needs to supervise teacup dogs 24/7. Their small size alone creates constant danger from things falling on them to other pets in the home. Many will have congenital and genetic health concerns. Respiratory problems, heart problems, digestive problems, hypoglycemia (low blood sugar), problems with the trachea collapsing or a permanent soft spot on their head caused by the cranial bone not completely forming. Dislocation of the knees, water accumulating on the brain, blindness, seizures, deformities, Leg-Calve Perthes disease (a degenerative disease of the hip joint) portosystemic shunts (an abnormal vessel also called a liver shunt. The dog's circulatory system bypasses the liver which is where the blood is cleaned). Their internal organs can be underdeveloped and their small mouth size has trouble accommodating all of their adult teeth which can lead to dental problems. Teacup dogs use up a lot of energy and calories just trying to keep their body temperature normal and can become malnourished even though they're well fed. A simple bout of diarrhea can leave them dehydrated which can be life threatening. http://voices.yahoo.com/teacup-puppies-buyer-beware-hidden-financial-health-6311618.html?cat=53IF
Buyer beware of breeders who guarantee their teacup puppies will be tiny. No caring and responsible breeder will make that promise because a dog's adult size can't be determined when they're still a pup. Size depends on genetics and you can get an idea of how big a puppy will be by looking at their parents and grandparents and knowing what the breed standard is for a specific breed.
they register the dog it's through an alternate listing since the size isn't recognized which is another huge red flag. Save yourself the heartache and hazzards and rescue from a reputable source, not a bad breeder trying to make space.