My Jersey is a year old and she has always had thin hair too. Earlier, in the year I noticed that her hind legs and her feet had barely any hair. Our vet actually noticed the feet and thought she had been chewing at her toes, but I told him no this is how it's been. Have you checked you Yorkies ears? Do they have black in them? If so your Yorkie may have skin allergies. Jersey has allergies and I'm told this is why she has thin and sparse hair and also this is why she has the heavy black wax build up. Allergies go to the ears and cause the black wax. Check his ears and see. I can clean Jersey's ears a couple of times a week and still the wax keeps coming back. By the way welcome to YT. Elaine |