How Long Does Shih Tzu Hair Grow Back? How long will a Shih Tzu hair grow? between 6 to 12 months. Which dog breeds can be shaved? Single-coated dogs include dogs such as Greyhounds, Boxers, Dalmatians, Poodles, Maltese, and Afghan Hounds. They can have very short hair or long hair, and it can be wiry, smooth, or curly but all have even ...