[Michael Romanos]

Re agiility - I was referring to all breeds and non-breeds and an overall pattern - not in picking out one or two examples.
Re breeding - Corgis are not usually tested here for hip dysplasia prior to mating. When the parentage and grandparentage is well known and documented I don't suppose Corgi breeders in New Zealand traverse down the pathway you infer. Good idea to have Corgi pups tested for any possible eye defect before they go to new owners and generally checked for any other internal/external problems. New Zealand has perfected a method of testing pups for vision. It is the result of dogs bred for guiding the blind having possible vision impairment - especially Labradors. In some cases in the past it's been a little like the blind leading the blind with the guide dogs relying heavily on their other senses.