Do you have a Petco?? They have a couple of high quality foods there. I would recommend the Solid Gold brand that they sell there. Check out
www.dogfoodanalysis.com The 4 star and 5 star foods are what they recommend for yorkies. Or you could continue to homecook for them, but get a good book that tells you how to do it correctly on a long-term basis. Get a book that will tell you what supplements they need and stuff like that. We homecook, and we make big batches and freeze in freezer bags what won't be used in the next couple of days. That makes it so much easier to homecook.