Few words in pet nutrition trigger more immediate panic than “by-products.” You see it on a label and suddenly the internet voice starts: “Fillers.” “Waste.” “Beaks and hooves.” “Low quality.” It sounds unpleasant. It sounds vague. And most of us don’t want to feed our pets something that feels like leftovers. But here’s the truth: The word “by-product” in pet food does not mean what most people think it means. Let’s slow this down and unpack it clearly. What Are By-Products