Teacup Pomeranians are few and far between. They are very rare and one can not predict the breeding of producing a teacup Pomeranian. The thing about teacups is that you do not know he or she is a teacup until the litter of pups is about three weeks of age. All of the puppies in the litter are born the same size and it is not until about three weeks of age that one of the pups starts growing at a slower pace. This puppy is not a runt because if it were a runt there would be a significant size difference at birth that would continue throughout puppy hood. The weight of the teacup from three weeks on would be half the weight of its siblings. Since the growing rate of the puppy is not noticeable until a few weeks after delivery, the classification is known as a "true teacup." A teacup puppy's mature adult weight is from 2 to 4 pounds and should weight about a half a pound at eight weeks old. Also a teacup will weigh and look half the size of its siblings.