The four definitions you need
Per the AAFCO Official Publication 2024, these are the rendered protein meal ingredients you will see on commercial dog and cat food labels, in decreasing order of traceability.
Chicken meal — the dry rendered product from a combination of clean flesh and skin with or without accompanying bone, derived from the parts or whole carcasses of chicken or a combination thereof, exclusive of feathers, heads, feet, and entrails. The species is named (chicken). Skeletal muscle protein dominates. This is the gold-standard protein meal under most rubrics.
Chicken by-product meal — consists of the ground rendered clean parts of the carcass of slaughtered chicken, such as necks, feet, undeveloped eggs, and intestines, exclusive of feathers, except in such amounts as might occur unavoidably in good processing practices. The species is still named (chicken). Organ tissue and connective tissue protein dominate. Less expensive than chicken meal because the source materials are less commercially desirable for human food, but still digestible and nutrient-dense.
Poultry by-product meal — same definition as chicken by-product meal but the species is not specified beyond “poultry.” This means the meal could come from chicken, turkey, duck, or any combination, and the proportion can vary batch-to-batch. Less traceable than chicken by-product meal.
Animal by-product meal — rendered mammalian product, exclusive of any added blood, hair, hoof, horn, hide trimmings, manure, stomach, and rumen contents. The species is not specified at all. AAFCO permits inclusion of any mammalian species, which means cattle, swine, sheep, or any combination. This is the least-transparent named-protein-meal ingredient and the one most often called out in pet-food consumer guidance.
Meat and bone meal (often shortened to “meat meal” in marketing copy) — rendered mammalian tissues including bone, exclusive of blood, hair, hoof, horn, hide trimmings, manure, and stomach contents. Species also unspecified. Higher mineral (calcium, phosphorus) content than animal by-product meal due to the included bone. Same traceability concerns.
Why “named” matters more than “by-product”
Pet-food consumer marketing has spent two decades framing the question as “by-product or no by-product.” Per the AAFCO definitions above, that frame is misleading. The harder, more useful question is: is the species named?
A named species (chicken, salmon, lamb, beef) gives the manufacturer a traceability obligation. Per the FDA Compliance Policy Guide 690.300, a manufacturer claiming a specific species in the ingredient list must be able to substantiate it on audit. Unnamed-species ingredients carry no equivalent obligation: animal by-product meal can shift between sources from batch to batch with no labeling change required, since the label simply says “animal.”
This matters for three reasons. First, dogs and cats with diagnosed protein allergies need ingredient traceability to do an elimination diet effectively — per the Olivry 2015 ICADA consensus, an elimination diet requires single, novel-protein-source feeding for 8 weeks before reintroduction. Second, manufacturers who use unnamed-species protein typically do so for cost reasons, which correlates with lower feed-grade sourcing standards. Third, a meaningful fraction of the recall record (per the FDA Pet Food Recall Database) involves unnamed-species rendered ingredients failing for Salmonella, mold mycotoxins, or pentobarbital contamination — the 2018 Big Heart pet food pentobarbital recall and the 2021 Midwestern Pet Foods aflatoxin recall both involved unnamed-species rendered components.
How rendering changes the math
Rendering is the process of cooking, grinding, and drying animal tissue to remove water and concentrate protein. Fresh chicken is roughly 70% water and 18% protein; chicken meal is roughly 10% water and 65% protein. That concentration is why a meal ranks high in the ingredient list relative to the same animal’s “fresh” or “deboned” cousin: AAFCO requires ingredients to be listed by weight before processing, and a high-water fresh meat ingredient outweighs a low-water meal even when the meal contributes more total protein to the finished kibble.
Per the National Renderers Association industry data, modern rendered protein meal achieves roughly 88-92% protein digestibility for high-quality chicken meal, and 75-85% for typical poultry by-product meal. The variance within unnamed-species animal by-product meal is wider, with reported digestibility ranges from 65-85%. This is why ingredient quality, not just position on the ingredient list, drives the rubric grade.
What KibbleIQ does with this
Under the KibbleIQ Dry Kibble Rubric, named species protein meals (chicken meal, salmon meal, lamb meal, beef meal, herring meal) earn full protein credit when listed in the top five ingredients. Named species by-product meals (chicken by-product meal, poultry by-product meal) earn partial credit, reflecting wider quality variance. Unnamed protein meals (animal by-product meal, meat and bone meal, “meat meal” without a species qualifier) carry a rubric penalty since AAFCO permits any mammalian source. The penalty grows when the unnamed meal appears in the top three ingredients, since position on the ingredient list correlates with finished-kibble protein contribution.
Bottom line
When reading a pet food label, look for the species name attached to every protein source. “Chicken meal” and “chicken by-product meal” are both legitimate, traceable ingredients with predictable nutritional profiles — chicken meal is higher-grade, but chicken by-product meal is not the boogeyman consumer marketing makes it out to be. The genuine red flags are unnamed-species ingredients: animal by-product meal, meat meal, meat and bone meal. If a manufacturer prefers to obscure the source species, the question to ask is what they are choosing not to tell you.
For brand-specific applications of these definitions, see our Purina Pro Plan review, our Orijen review (named species first ingredient), our Acana review, and our Pedigree review (unnamed by-product meal first ingredient). For ranked recommendations using only named species protein, see best dog food overall.