Crude protein in poultry: the myth we still haven’t killed

We still talk about “protein levels” in feed as if it’s 1985. Ask most producers what they’re feeding and you’ll hear “a 20% protein grower” or “an 18% layer mash.” We’ve built entire diets around a single number that tells us almost nothing useful. Crude protein doesn’t grow animals — amino acids do.

Crude protein is just nitrogen multiplied by a constant (6.25). It doesn’t tell you if that nitrogen comes from lysine, from fiber-bound residues, or from urea contamination. Yet we still price and compare feeds by that meaningless percentage. A diet can hit 20% protein and still be deficient in methionine or threonine — and the bird doesn’t care that the label looks good.