The scores
Kirkland Signature Adult Chicken, Rice & Vegetable: B (78/100) — Chicken, Chicken Meal, Whole Grain Brown Rice, Cracked Pearled Barley, Chicken Fat.
Purina Pro Plan Savor Shredded Blend: C (58/100) — Chicken, Rice, Whole Grain Wheat, Poultry By-Product Meal, Whole Grain Corn.
How the ingredients compare
Here are the first five ingredients on each label — the part of the panel that drives most of the score under our published rubric:
Kirkland: Chicken, Chicken Meal, Whole Grain Brown Rice, Cracked Pearled Barley, Chicken Fat
Purina Pro Plan: Chicken, Rice, Whole Grain Wheat, Poultry By-Product Meal, Whole Grain Corn
The score gap lives in positions three through five. Both recipes lead with Chicken, but Kirkland follows with Chicken Meal — a second concentrated, named animal protein — while Pro Plan’s second slot is Rice. From there the panels diverge sharply. Kirkland fills its next three with Whole Grain Brown Rice, Cracked Pearled Barley, and Chicken Fat: identifiable whole grains plus a named fat source, all of which our rubric treats neutrally or favorably. Pro Plan instead stacks Whole Grain Wheat, Poultry By-Product Meal, and Whole Grain Corn. Wheat and corn are lower-value grain fillers under the rubric, and Poultry By-Product Meal — an unnamed, rendered mix — is penalized relative to a species-named meal like Chicken Meal. That is three rubric demerits in Pro Plan’s first five versus none in Kirkland’s, which is exactly why a cheaper store brand finishes 20 points ahead.
Where Kirkland pulls ahead
Two named proteins up front: Kirkland doesn’t just lead with Chicken — it backs it with Chicken Meal in the second slot. Chicken Meal is rendered chicken with most of the water removed, so it concentrates protein into a smaller weight, and because it is species-named you know exactly what animal it came from. Our rubric rewards named animal proteins and treats meals as a strength when they are specific. Stacking fresh Chicken and Chicken Meal in the top two positions is the single biggest reason Kirkland reaches B (78/100). Pro Plan’s second ingredient is Rice, a carbohydrate, which pushes its animal-protein density lower in the panel. For owners who read labels and want protein, not starch, sitting near the top of the list, this ordering is the clearest signal of quality and the core of Kirkland’s advantage here. Shop on Amazon →
Cleaner carbohydrate sources: The grains Kirkland chooses matter as much as where it places them. Its third and fourth ingredients are Whole Grain Brown Rice and Cracked Pearled Barley — both whole, recognizable grains the rubric treats neutrally rather than penalizing. Pro Plan’s carbohydrate slots are Whole Grain Wheat and Whole Grain Corn, two of the most common lower-value grain fillers, which our rubric marks down. Neither corn nor wheat is dangerous, and many dogs digest both fine, but on a comparative ingredient grade they cost points where barley and brown rice do not. Kirkland also rounds out its first five with Chicken Fat, a named fat source, instead of an unnamed one. The net effect is a top-five panel with zero rubric demerits, which is rare at any price and especially at roughly $0.90–$1.25 per pound.
Quality-per-dollar nobody else touches: Kirkland sells for roughly $0.90–$1.25 per pound, while Pro Plan typically runs about $2.00–$2.60. Paying less for the higher ingredient grade is unusual; normally a B-tier panel commands a premium. Diamond Pet Foods manufactures Kirkland to Costco’s spec, and the formula reflects deliberate choices — two named proteins, whole grains, named fat — rather than cost-cutting fillers. For a multi-dog household or anyone feeding a large breed, the monthly savings against Pro Plan are substantial while the rubric score is higher, not lower. That said, the value only exists if you can buy it. Kirkland is sold essentially only at Costco, so the membership fee and the trip are part of the real cost. If you already shop there, this is arguably the strongest mainstream value in dry dog food we score.
Where Purina Pro Plan holds its own
Feeding-trial substantiation: Pro Plan Savor is substantiated through AAFCO feeding trials — dogs were actually fed the diet and monitored — rather than meeting nutrient targets on paper alone. Our ingredient rubric does not score this, because it grades the panel, not the testing protocol, but it is a real point in Pro Plan’s favor that no ingredient list can capture. Feeding-trial validation gives some owners and many veterinarians added confidence that the food performs in living animals over time, particularly for puppies, seniors, or dogs with a history of finicky digestion. Kirkland’s substantiation method is typically formulation-based. If feeding-trial evidence is a hard requirement for you — and for some vets it is — that consideration can reasonably outweigh a 20-point ingredient-panel gap. It is the most legitimate reason to choose the lower-scored recipe here. Shop on Amazon →
Vet trust and consistency: Pro Plan is one of the most veterinarian-recommended mainstream brands, and that reputation rests on more than marketing. Nestlé Purina runs large-scale quality control and has decades of batch-to-batch consistency, which matters for dogs whose stomachs react to formula changes. The Savor Shredded Blend texture — kibble mixed with shredded pieces — also drives strong palatability, so picky eaters often accept it readily. None of this changes the C (58/100) ingredient grade, but real-world feeding is about more than a label. If your dog already thrives on Pro Plan, the rubric is not a reason to switch; a food your dog reliably eats and digests beats a higher-scored one it refuses. Stability, acceptance, and a long track record are genuine strengths, and they are exactly the things an ingredient panel cannot show you.
Buy it anywhere, no membership: Pro Plan is sold nearly everywhere — pet specialty chains, big-box stores, grocery, and every major online retailer — with no membership required. Kirkland’s higher grade comes with a real catch: it is available essentially only at Costco, so you need a paid membership and a warehouse trip, and third-party online resellers often mark it up enough to erase the savings. If you are not a Costco member, or you travel, or you simply want a bag you can grab on short notice from any store, Pro Plan’s ubiquity is a practical advantage that a score does not reflect. Purina also offers Sport/Performance and Sensitive Skin sub-lines, so you can stay within one trusted, widely stocked family if your dog’s needs change. Availability is not nutrition, but a food you can actually keep in the bowl is the one that counts.
The bottom line
On ingredient quality, this isn’t close: Kirkland Signature Adult Chicken, Rice & Vegetable earns a B (78/100) and Purina Pro Plan Savor Shredded Blend lands a C (58/100), a full grade tier apart. Kirkland leads with Chicken and Chicken Meal over whole grains and named fat; Pro Plan carries Whole Grain Wheat, Poultry By-Product Meal, and Whole Grain Corn — the rubric’s penalties — and does it at roughly double the price. If you are a Costco member, Kirkland is the clear pick: a higher-graded panel for less money. But C (58/100) is not a bad food, and Pro Plan earns its keep on feeding-trial substantiation, deep vet trust, reliable palatability, and being sold everywhere with no membership. Pick Pro Plan if those practical and clinical factors matter more to you than 20 points of ingredient grade, or if a warehouse run simply isn’t realistic. Both are sound; only one is also a bargain.