This is one of the biggest problem with puppy mill pups.. They buy cheap dogs that should never be bred or reg for sale as yorkshires, then mass breed them. Many have so many issues as you have described..Did you turn the breeder in as a puppy mill???? I don't care if they have 2 dogs if they are not in good health or being fed right you should have turned them in..I've seen dogs people have paid good money for the same way... Ugh! Many look like that little mexican dog with hair stuck to them.. I had someone bring a yorkshire to me a few weeks ago trying to give it to me.. I felt it's coat and it was straight but really wirery.. I've never felt a coat like that before. He didn't have much hair on his legs either and no hair on ears.. I love the puffy faces with tons of hair..I've been breeding my line for over 24yrs.. They are hairy..
I don't ask huge prices for my dogs either and many live well into their teens..You have to have good genetics for dogs to be living 15 to 19 yrs.. Not many people even have them that long that are breeding.. get references or do more research on line as to a healthy dog and what they should look like as pups... LOOK AT THE PARENTS.. IF THEY HAVE NO HAIR YOUR PUP WILL GROW UP HAVING NO HAIR... Good luck with your little guy as he needs you so much.. so sad though... Feed him good and I would add vitamines and goats milk to his diet, scrambled eggs.. Also I found Purina moist and meaty dog food dose make a coat look better...But I guess you have to have one to do so...
