Do some really serious searching. Ask a million questions. After all, your getting ready to hand over some serious money to adopt a fur-kid and you want it to live a very healthy life for many years to come, and not spend a lot of time at the Vets.
http://www.dogup.com/yorkshire-terri...north-carolina http://www.hoobly.com/0/0/202433.html
You could start with these people and ask lots of questions, and maybe go see their operation and puppies. If they are too far, then just ask them if they know anyone in or around your area who has nice healthy Yorkies with health guarentee and bile acid testing.