Yorkies Diet
Here at DR Yorkies, we use Eukanuba brand dog food.  This food has no fillers in it, and works great with my small breed yorkie puppies, especially the teacup size.  Here is a link to their web site, where you can check out the ingredients for your self. www.Eukanuba.com

Regardless of which food brand you choose it needs to accomplish certain goals that you should have in mind for your puppy.
Is puppy gaining weight?
Is puppy maintaining weight?
Is the coat shinny and the eyes bright?
Is the dog's energy level good?
Does the yorkie like the food?

Learn through careful evaluation
When looking around for a different food for your dog, be careful about a sudden switch in your feeding patterns.  This can cause an upset in your puppy's stomach.  However, you can do a gradual switch, by mixing your dog's regular food with another brand.  By doing this you can do a careful evaluation for better results in your feeding.  Protein is the most important ingredient in your dog's diet.  Look for the protein content at the top of the ingredients on the food label.  Yorkie's are very well known for being picky eaters at times.  If a tiny puppy feels a little off balance and fails to eat for a day, you can be in for a big problem.  They can experience a drop in sugar, and literally become so lethargic they can become unresponsive.  Hypoglycemia is the medical term for low sugar.  Breeders often refer to this as sugar shock.  This is a potential problem in all Yorkshire Terriers, and especially young ones.  My experience is that sugar shock is more prone to occur in Yorkie puppies between 5 to 9 weeks.  That is why a teacup Yorkie needs to be held past the usual 8 weeks sale date.  This is more so true if the Yorkie puppy is being shipped.  A plane ride or even a car ride can be very stressful on these little teacup Yorkies.

Treats and your puppy
Treats with a little kick in them can go a long ways in keeping your puppy satisfied.  Honey nut cheerios is a great treat as well as vanilla flavored yogurt.  Keep a jar of the pre packaged snacks at hand.  These can also work great when you are teaching your puppy the potty training basics.  A little treat can go a long ways in helping a young puppy remember that it isn't' supposed to relieve itself inside on the carpet.  A tiny yorkie will also need wet foods when very young or when they are not feeling up to their usual self and you think there may be a drop in sugar.

Check with the manufacturers
If you are searching for a good dog food, contacting the manufacture about their product is a good idea.  If their product is one that they are proud of, they will be willing to share their products success stories with you.  Checking on the internet is also a good way to gain information about successful feeding.  Also you can check with the breeder that you bought your baby from.  They  have had lots of experience in yorkie diet, and they can share many pros and cons with you.

Free Feeding
Leaving a bowl of feed in a place where your small puppy knows they can always have access too, is usually a wise idea.  If you choose not to free feed, it is advisable to have regular timed feedings.  Make sure there is always water at the feeding area.