He is undersized. The Continental Kennel Club is not a recognized bona fide registry for purebred dogs.
A male or female in any breeding program should be among the best and should be contributing to the betterment of the breed by producing progeny.
Breeding just because you can, ie have breeding rights, is not a good reason to breed.
One that small at that age, I would worry, He should have BA and a general blood panel to be sure kidney/liver function is normal. Often they can be unusually small due to a health issue, some of which cannot be tested for. |