A lot of the time, when someone sees a dog wearing a muzzle, the first thing that springs to mind is that the dog must be vicious, but there are many reasons why a dog might be wearing a muzzle. Here is Breakthrough Veterinary Advisor Vicky Payne BVetMed, DipCABT (RQF level6), GradDip VWHM, MRCVS with information about muzzles and how to muzzle train your dog.