"because a teapot can hold more sugar then a teacup" Ohhhh how I love this 
 
 
 My Suzi , is perfect. ANd i do  not even know how much she weighs! Somewhere between 7-8 LBS  . She seems small to me, for a full grown dog she is still little. Her mother only had 3 puppies, and she was the only female. 
  As long as your Yorkie is healthy it does not matter how big or small you have em. However, I worry about the little tiny ones, because they are so delicate and fragile . Their adorable as can be, but, I'd be a nervous wreck owning one.