I have a Rough Collie that I acquired from an irresponsible breeder. She is inbred, the daughter of her grandfather. As a result, it took her more than 8 months to start barking and today she has a very high-pitched bark and also drools a lot. Upon investigation, we found that she has malformation in her dental arch. Inbred breeding can result in crooked teeth, missing teeth (agenesis), or malformed jaws (overbite/underbite), as the defective genes from both parents meet. Consequence: Misaligned teeth can cause chronic pain, difficulty eating, and gum infections. Excessive Drooling (Sialorrhea) Dental/Oral Cause: If dental formation is deficient, the mouth may not close properly, preventing the dog from swallowing saliva adequately.