Growth rate depends on your dog's breeding lines. Some mature to full size early, others are late bloomers. Many Yorkies are full grown by 1 year of age and develop muscle mass in their second year, adding to their weight.
My boys are full brothers and had growth spurts at 11 months of age. Teddy was really a late bloomer. He was just under 6 pounds at 8 months of age. He is a skinny 8 pounds 6 ounces full grown.
