Do boxer dogs have under bites?

Answer 1

If the dog has not been spayed or neutered, then yes, it is possible to breed it. But it would be highly discouraged to breed any dog that has such a physical abnormality. The genetics that caused the underbite in your dog could easily be passed on to the resulting puppies.

Answer 2

Yes, they do have an under bite, where the lower jaw protrudes somewhat beyond the upper jaw.