That's not true at all unfortunately.
If you get from a VERY good breeder (& not just a BRC or backyard one), they may well know all about genetics & have kept a family line of buns to know that they won't develop problems later on. But most (not all
) breeders conditions are not up to scratch, they over-breed, or breed indisciminantly (not knowing a substantial history of the bun they are breeding from) & sell bun when it is young & health problems have not yet been established.
Although you will meet all this in buns in Rescues, the Rescue is more likely to know the bun - an older bun has an established personality/has been neutered/spayed so already had a vet check, & they make no profit so are in no way tempted to "make a sale".
If you DO decide to go to a breeder - I'd "homecheck" THEM. A good one would be happy to show you their buns & premises. Then I'd want to know the history of bun I was getting (several generations) & see parents/certificates. And I'd want it rung. (Which I'd immediately remove!:lol