The medical definition of epilepsy in dogs (defined as Idiopathic epilepsy) simply means "seizures from an unknown origin". Can you blame the breeder or say Really that it's anything to do with either dogs when siezures can come on from so many different factors. Arthritis also can be from more then a poor breeding pair. Could be from damage done earlier in life that only the owner or possibly just dog may have been involved with. Or quality of life can also factor in also what dog has been fed. Out of two litters only two pup's were found to be unhealthy? How many were born from those two litters? How many puppies out of the two bitches otherwise? Any other il-health traits that you know of? Another question what do you mean by being asymptomatic? Asymptomatic means there are no symptoms. So do they have something that is known but not causing any effects? Or do they have a clean bill of health?