@RockOnTommeh, happy to help! I'm probably going to enter 'teacher mode' so apologies in advance if it sounds a bit teachery or preachy! I don't mean to!
Some dogs breeds are prone to severe elbow and hip issues. It's called 'dysplasia' which essentially means the hip or elbow joint hasn't formed properly. Dogs can be born with it and they can be genetically pre-disposed to get it as they get older. It's incredibly painful and can, in severe instances, stop the dog from being able to run or even walk without being in agony. There's a poster on mumsnet with a lab with really bad dysplasia and she has to take it to physiotherapy and swimming etc. It's not just about the pain it causes the dog, but also the financial strain (and I don't mean that to sound crude, but medication and treatment for things like dysplasia can very quickly add up).
The scoring system is pretty basic. The higher the number, the higher the chance a dog has of getting dysplasia. So, the lower the number the more confident you can be that the dog is healthy and won't develop dysplasia as it ages and, in turn, any offspring that dog has should have a lower chance of getting dysplasia.
Each 'elbow' (front legs) and 'hip' (the back legs) is measured against particular criteria. Those numbers are then added together to give an overall score. For elbows the maximum you can get is a '3' in each elbow and the lowest is '0'. For hips, the maximum you can get is '53' and the lowest is '0'. There's more 'flexibility' in hip scores (as is probably obviously by the higher number 53] compared to elbow scores [3]).
So, Hips: 8/8 : that means that each hip has been given an 8 out of a possible 53. The breed average is 17 altogether across both hips. So 8/8 would mean the dog had 16 altogether. My girl has a score of 2/3 in her hips. That means that one of her hips got a 2 out of 53, and one got 3 out of 53.
Ideally, you want dogs with the lowest possible hip scores. But it's not unusual for dogs hips to have quite different scores. So you could get one who has a Hip score like this: 4/13. Which, in theory, is good news - because it means the dog is perfectly at the breed average. But it's also bad news because that can lead to overcompensation (in very basic terms) by that dog because one score is actually very high (13 is not a good score, even though the overall average of 17 is perfectly average - if that makes sense). And then if the other parent has similar scores...you're in for a bit of a tricky time.
For elbows, I would never choose a stud with a score higher than '0' because if the maximum is '3', why would you got for a dog with a score of '1'?
Essentially, when you're buying a puppy you're not just buying the puppy. You're buying it's parents and the breeder as well. You're buying the pups parents health, and the breeders time and investment in the pups.
A live example would be to go to the KC website, search 'find a puppy' and enter 'Golden Retriever.' Click the one from 'Norwich' (Both parents fully health tested). I've used Goldie's as that's what I breed, so I know them like the back of my hand!
When you use the KC website and search through litters, it'll show you how health tested the dam and sire are (you should want 'fully health tested' -'KC good practice' or 'min 1 health test' is not good enough IMO because those health tests are there for a reason).
So, on this litter. The sire is Ovlinglay Locksmith. If you click on his name it'll take you to a page with all his details. You'll see all his health tests, how often they were done etc. Good breeders will have their dogs health tests done very few years (in sire's) and before every litter (dams). You'll see Ovinglay Locksmith has very good scores. 0:0 on elbows and 5:2 on hips. There's also an 'inbreeding coefficient,' which (essentially) relates to how inbred the dog is as a result of his parents and grandparents, along with a breed average. The lower the score the better. So for Goldies, the breed average is 6.8 but Ovinglay Locksmith has a score of 9.1%. So, overall, I'd say he's a pretty good stud. He's got good health scores, he's been recently tested for eye conditions.
The dam is Camelia Sweetheart. Again if you click on her name you can see all her health tests. All fairly good. Her hip scores are a bit high at 5:7 - but still below the breed average. She's quite inbred at 14.1%. So, overall I'd say she's a reasonable dam.
But that's not all there is to it. You have to compare them together, so if you navigate back to the main page of the litter, click on one of the pups. So, this breeder has done some health tests on her pups already. That's good. Then you can scroll down and see how inbred the pups are - 7.9%.
What does this mean for the puppies? Parents hip scores are well below the breed average (5:2 and 5:7 respectively) and their elbow scores are perfect (0:0). The puppies will only be 1% more inbred than the breed average, which is good. The parents both have clear eye exams. If you bought a puppy from this litter you could probably be fairly confident (in so far as you can ever be with genetics) that the puppies would live pretty healthy, happy, lives.
But, the real benefit with a pedigree, is that you can see the health test scores of the grandparents. So if you click on Ovinglay Locksmith again and scroll to his 'family tree' you'll be able to click on his parents (so the puppy you'd theoretically be buying grandparents) and look at their health tests. Likewise, for the dam.
What you'll see from them is that, over time, the dogs have become 'healthier' because of selective breeding (for example one of each 'grandparent' to the current litter had an elbow score of 1:0). Likewise, you can see the great-grandparents health tests etc.
As I said, that's the real benefit of buying a pedigree - all of this is available to you at the click of a button. The problem with designer dogs is that this isn't readily available and many of the best breeders of the pedigree dogs (i.e. those breeders who have spent years breeding the healthier dogs they can) won't stud their dog out to produce designer doodles.
I do genuinely have nothing against designer doodles as a breed (personally I think cockerpoos are quite attractive little things and I can certainly see the appeal). I just think finding a good breeder for them, finding all the health tests for parents and grandparents etc, is really hard if not downright impossible.
And, at the same time, I understand the dislike and distrust people have of pedigree breeders. The Kennel Club has made a lot of mistakes over the last few years,
Overall, I think a lot of people can be a bit blase when it comes to finding a breeder and a puppy. Finding a good breeder takes time - weeks and months - and there is a very high chance that, to get your perfect happy, healthy, puppy, you will have to wait.