Malodorous breath is most consistent with dental disease. In this still fairly young age range, it may seem unusual for a dog to already have significant dental disease, but many dogs, especially small to medium sized breeds, are genetically predisposed to dental disease and have significant tartar and gum disease even this young. If you still seek further information, please visit our Ask The Vet page to submit a one on one consultation with a licensed veterinarian 24 hours a day, 7 days a week.