Just wanted to share something for all you parents of picky yorkies. My yorkie/Jack Russell mix, Vincent, has always been a VERY picky eater. I adopted him at the age of 1 and he was severely underweight. I tried every dog food on the market and then began cooking for him at home (chicken, beef, veggies, etc). The home-cooking was a lot of work and he didn't always eat enough to maintain his weight.
About 4 months ago, an "all natural" dog store opened up in my neighborhood. I was in there one day lamenting about Vincent's poor eating habits and the owner gave me free samples of Nature's Variety (
http://www.naturesvariety.com/). I tried both the frozen/raw medallions and the dry food and was AMAZED when Vincent finished every last bite.
He is now at a healthy weight and eats every meal without any begging, force-feeding, or bribing on my part. He especially loves the raw beef medallions. The only thing he still won't touch is anything that comes out of a can. I highly recommend that you try this food brand if you're having trouble getting your yorkie to eat. It's a tad pricey, but well worth it!