I woke up this morning and thought of a website that might give you some info- it
has me through the years. I'm in a hurry so I can't go through it but I'll give it to
you just in case you haven't done research on it already. You can trust it, it was
complied by the Yorkshire Terrier Club of America. Welcome to YT and Good Luck.
http://www.rievaulx.org/health.html