
The hip test you mention is called Hip Scoring for Hip Dysplasia. You take a dog to a vet and have their hips X-rayed, the plates are then sent to the British Veterinary Association to be assessed by experts who measure the amount of hip dysplasia and give a score. They provide one figure for the left and one for the right, added together this gives the hip score. The best possible score would be 0/0 and the worst 53/53. There are published mean scores for each breed and you would wish to find that both parents of your prospective puppy score below the breed mean, which is currently 15 for the Labrador Retriever.
Dawn R.