Every yorkie is an individual just as people are, therefore, different kinds of food affect each yorkie differently. Try to stick with foods that don't have corn in them. Many yorkies tend toward allergies and corn is a big culprit. There are many good dry foods out there. We have a special liking for Natural Balance at our house. Good luck and please keep us up to date on your special new addition.
You can look at this site and see the ingredients listed on the different brands of food at the bottom of each page:
http://www.petfooddirect.com