Well, some of the foods are All Life Stages which means that they can be given to puppies, adults, and seniors. The amount will depend on the age. For example, a puppy needs more calories than adults, so a puppy will eat more calories than an adult.
Canidae, Natural Balance, and Merricks are All Life Stages foods.
Here's a link that explains it:
CanidaeŽ Pet Foods: Why Choose Canidae All Life Stages
If you go with a food that is *not* All Life Stages, it's important to make sure that it's specifically for puppies. I believe Innova and Solid Gold have puppy foods that you can give.
Small bites are always good, but some yorkies don't have problems eating regular sized pieces of kibble, so it may not be necessary for your baby.