Hotlikebikramyoga, I'm not familiar with dachshund breeders since mine was a rescue but I do know a few reputable labrador breeders. Most of them raise their litters on foods like Pro-Plan, Royal Canin, or Eukanuba. They like these foods because they are tried and true in giving them slow even growth which is really important in labs because they are prone to orthopedic issues.
I know one breeder that has tried raising litters on a premium brand but ultimately went back to Pro Plan because it just did not give the same results. The litter's growth was all over the place.
As the owner you are entitled to feed whatever food you want but just know that just because a food is a premium food does not mean it is the "best" food for a dog. The best food varies from dog to dog. Some dogs do terrible on "premium" brands and can only tolerate middle of the road foods like Pro-Plan.
I really think that the breeder feeds is low on the priorities list in finding a reputable breeder especially since if you are not crazy with what they feed you can always change it to something you are more comfortable with after a bag or 2. I would caution against changing brands immediately when bringing home a puppy. Coming home is already stressful for them, no need to make it more stressful by adding a new food to the mix.