Overview
A Shih Tzu is technically a puppy until the age of 2 years old. However, this breed will be most vulnerable and in need of your care when he or she is going through the puppy weaning process.
A large part of puppy care is the weaning process. If you obtain your Shih Tzu when the dog is at a very young age, it will be your responsibility to help the pup wean from mom's milk in a healthy way.
When this process is rushed, it can cause health issues to the puppy. Malnutrition may occur. Additionally, studies have shown that when the steps are not followed carefully, food allergies may develop. Those intolerances to foods may affect a dog's health for their entire life.
In almost every state in America, it is illegal for a puppy to be taken away from its mother before the pup is 8 weeks old. Responsible Shih Tzu breeders will allow the puppy to stay to drink its mother's milk until the age of 10-12 weeks.
Therefore, most likely, if you have a Shih Tzu puppy, the youngest age it should be is 8 weeks old. Learn how to properly feed your little bundle of fur to maintain optimal health.