Have you checked out the YT library for threads on this subject? There is so much to learn before considering to breed. Heck, it's my understanding that there is tons of studying to do before you are even qualified to qualify if a pup is of breeding quality.
Don't feel like I want to discourage you from breeding, because I'm not. I want to discourage you from being a bad breeder. First you must find a mentor to teach you everything there is to know about the yorkie, what constitutes standard, what classes to take on canine genetics, what tests need to be done on the breeding pair, how to study a pedigree, and most importantly of all, find someone who is experienced in breeding yorkies so you know when you and your girl are in trouble.
Personally, from one new(ish-
) yorkie momma, don't do it. There is too much risk involved and not much to gain if you into this somewhat blind. It is flattering to have people come up and say they want a pup just like yours. An old co-worker wants to pupnap my boy because she's in love with him. My friend and I have also been approached by random strangers in the street asking if we would breed my neutered boy and her spayed girl because they want a puppy. That's very flattering, but my boy is going to live the lavish life of a spoiled baby instead.
