I just got to thinking.. Where exactly do feeder rabbits come from?

I bought a baby flemish giant a few weeks ago from a breeder. She was going on about how she would probably sell him to the zoo as a feeder when I came to pick one out of the three, because he had a blue coat like the rest of the litter but a little bit of white at the end of his tail that would disqualify him from showing. So, I just said, nuh-uh, he's mine. :3 He has an amazing personality and is a joy to have around; gotta work on litter training a little. So, I understand that our reptiles have to eat too.. But where do most (live) feeder rabbits come from? Just out of curiosity. From show breeders, pet stores, "feeder breeders", etc.?