Experienced & Show Breeders I was looking at Yorkshire Terriers and came accross this:
Will be small 4-5 pounds, little face, and
precious personality. He does have what they like
to call the
Yorkie Shake, which this is my first
experience with, but it is like the Chihauhau
tremble, no health problems are liked to it, but
keeps them out of the show ring for sure.
What is the "Yorkie Shake"???
Has any of you Experienced & Show Breeders ever heard of it?
What causes it?
Is it Bred into the Yorkshire Terrier Breed?
Is it Gentic?
Can it be bred out of a line?
I never heard of the "Yorkie Shake" before....Never seen it, so it has me question what it is....I tried to look it up on the internet, couldn't find anything. Please I'd love to learn about this. 
Lee