I Really suggest you look at this website, it is from the University of Tennesee, wher Dr Tobias is, she invented the corrective surgery and deciates her life to yorkies with liver shunts and MVD, I took the trip out there to see her, THE BEST!!!
The University of Tennessee - College of Veterinary Medicine - Portosystemic Shunts
Bile acids are only indicators of liver /gall bladder problems , but usually in yorkies it id due to a liver shunt or MVD (microvascular dysplasia).
As far as the breeder, do you get a health garantee(contract signed?) If not there might not be much you can do
