Native food supplies for Yorkies would have been rodents, a dairy cattle form of beef, potato, sugar beet, rye, and barley.
For the Yorkshire Terrier I recommend foods that are a blend of horse and beef meats, sugar beet, potato, wheat, and barley. I also suggest you avoid feeding a Yorkie any red fish, such as salmon, yellow corn, or soy.
Fresh food. Fresh chicken and turkey and beef. Fresh raw vegetables and fruits. Fresh brown rice and oatmeal. Fresh yogurt, eggs, and cottage cheese
BAD FOOD.....
Baby Food:
Can contain onion powder, which can be toxic to dogs. Can also result in nutritional deficiencies, if fed in large amounts.
Bones from fish, poultry, or other meat sources:
Can cause obstruction or laceration of the digestive system.
Fat Trimmings:
Can cause pancreatitis.
Milk and other dairy products:
Some adult dogs and cats do not have sufficient amounts of the enzyme lactase, which breaks down the lactose in milk. This can result in diarrhea. Lactose-free milk products are available for pets.
Other another website for questions on Yorkie
http://www.askariel.com
Raw Eggs:
Contain an enzyme called avidin, which decreases the absorption of biotin (a B vitamin). This can lead to skin and hair coat problems. Raw eggs may also contain Salmonella.
Raw Fish:
Can result in a thiamine (a B vitamin) deficiency leading to loss of appetite, seizures, and in severe cases, death. More common if raw fish is fed regularly.
Toxic Plants:
As we let our dogs roam freely in and out of the house, we need to be aware of what we are exposing our pets to. There are various plants that are poisonous to dogs both inside and outside of our homes. See the attachment for a chart of some of the more common plants our dogs may come in contact with.
Here is a link incase you can't read the attachment:
http://www.entirelypets.com/toxicfoods.html