Welcome to Yorkie Talk!
Yorkies are awsome critters.
I would have two (non-judgemental) questions for you:
1. I'm interested to know what interests you about the Yorkie?
2. What type of Service Dog are you hoping to train/have trained?
Again, Welcome
The folks here are not vets but there is a powerful amount of knowledge about the breed here - and they are very generous with their help!