
That soes depend on whether the pups was sold as a breeeding anumal (very stupid of a breder with an immature animal) or as a comapnaion with maybe show/breeding potential.
the dog is not unfit for the purpose (a companion) due to the absense of a testicle, failure of ear carriage, poor tail carriage or wrong bite etc etc, all of which can go wrong in a puppy making it an adult that is not fit to be bred from and or shown.
Most breeders chatge the saem for all their pups at the baby stage, as they at best can have potential at that stage, but it shoudl be evident that they are fit to be companions by then, and that is what is being sold. Those who are chatging extra for breeding or show woudl in my view be morally obliged to refund the difference of price paid and that of a pet pup, or depending on what was agreed exchange it for one that met the contracted purpose.