I recommend a private serious hobby breeder. But you will have to ask some questions before you buy.
Where did they get their stock from? How long have they been breeding? What are their breeding goals?
No bird is perfect, but most hobby breeders love to point out all the virtues of their birds and to talk about how they hope to improve their flock even more (tell you the flaws). They will tell you where on the scale they value egg laying and health. They will happily tell you how well they have done in shows, which tells you how close to the standard the birds are.
Don't worry that they will be offended by questions. Most show breeders, the problem you have is to get them to shut-up after they start talking about their birds.
Show birds cost more. So if you are on a budget, buy fewer birds and then hatch out as many as you need. Chickens lay a lot of eggs. You can hatch out a lot of nice birds if you are starting with no more than a trio of quality birds.