Hi! Thin hair in a puppy usually means they will have a nice silky coat, not a wooly one. The ones with tons of hair really early, are darling, but often have a wooly coat that is harder to groom because of mats. Yorkies go through so many changes in the first year, so it is hard to tell how they will end up. There is a lot to be said for both types of coats, any Yorkie is darling. So just take good care of your baby, and enjoy all the changes as they come. A good quality food, and maybe a supplement will help nature on its way. Congradulations on your baby. My Sawyer had very thin hair, but he is 8 months now, and it is coming in nicely and very silky.