Do yorkies stay small

dear questioner it depends on number of things which make a Dog or a puppy stay small for life! malnutrion,breed's genetic make up of bone structure,lack of excercise. now the thing is 'small' in what way? for ex, a german shepherd must reach atleast 22 inches at shoulders at maturity but if given diet of high protien but with very low calcium diet it won't reach 22 inch @ shoulders.