
I look after a friends Yorkie when they go away, and she only has the very bottom of a Kellogs cereal bowl covered with food.
It is very easy to overestimate how much they need, they eat a lot less for their size than a cat.
My 20kg dogs only eat about the same as my Dads cat, and that is 6 ounces of a high quality complete food. At times when I have had to put one on a diet then they only had 4 ounces.
I would estimate that the Yorkie got less than 2 ounces, but she was older. The amount of treats she has would probalby equall half her food, and you should aim not to give her so many as they are not properly balanced.