That's not an easy question to answer as there is no single "Universal Best Food for ALL Yorkies." And there are many options regarding diet--commercial, home cooked, raw and any combination imaginable in between.
A few suggestions to help you in your search for the 'perfect' fit for your little one:
While dogfoodanalysis.com has alot of good info--it's based entirely on the opinion of the site editors, not long term professional research. Please do not let your search start and end on that site, with one opinion. Another site you may want to include that links you to information from various sources regarding various diets as already mentioned is:
Dog Food Review Ratings
Also, if you look at the top of this section of YT, there is a sticky with a list of commercial food manufactures that give you their contact info--many of them will send you free samples to try and coupons for their products if you contact them and request them.
Finding the perfect option for YOUR dog will take trying different options and observing the results you get from them, but eventually, you will find a good fit.
Good luck and welcome to YT.
