So don't.As the breeder, you have the choice on who you do business with. It really is that simple.
To be fair, your thoughts are absolutely valid. As a breeder, it's rare that you're 100% certain your animals are going to receive exceptional care in their new homes - whether they go to stores or individuals. All you can do is your best during your interactions and conversations with potential customers to learn if they're a good fit for the animal(s) they're intending to purchase. Beyond that, there's not much you can do.