Dogs should ideally be taught from a young age, where muzzle training can be fun, how to wear a muzzle. Any dog who is fearful or in pain, at any point in their lives, can bite. It is good practice to teach your dog to find wearing a muzzle a positive experience, because if it is ever necessary for a muzzle to be placed, then the dog does not find it an added aversive to the situation. A dog can still bite through a muzzle and there is always a chance that a dog can get a muzzle off. Muzzles do not guarantee that the dog won’t bite or cause harm.
The type of muzzle found to be easy to start muzzle training with is a Baskerville or Basket muzzle. They are available in most sizes to suit all breeds of dogs: