The scores
Iams ProActive Health Smart Puppy Original with Chicken: B (75/100) — Good. Whole chicken first, chicken fat preserved with mixed tocopherols, fish oil for DHA, and a probiotic-free but AAFCO-compliant growth formula.
Hill’s Science Diet Puppy Chicken Meal & Barley Recipe: C (58/100) — Okay. Chicken meal first, then three grains (wheat, barley, corn) before the chicken fat arrives at position five. Vet-recommended by reputation, not by rubric.
How the ingredients compare
The top five ingredients:
Iams Smart Puppy: Chicken, Ground Whole Grain Corn, Chicken By-Product Meal, Ground Whole Grain Sorghum, Dried Plain Beet Pulp
Hill’s Science Diet Puppy: Chicken Meal, Whole Grain Wheat, Cracked Pearled Barley, Whole Grain Corn, Chicken Fat
The ingredient-list architecture is the 17-point story. Iams leads with whole chicken — fresh, water-in muscle meat — then builds the kibble matrix with corn and sorghum. Hill’s leads with chicken meal — which is a more protein-dense form of chicken pound-for-pound, but by dry weight the Hill’s top five carries three grain ingredients (wheat, barley, corn) before any fat source. Iams hits chicken fat at position seven; Hill’s at five. Neither is a premium formula by any measure, but the rubric penalizes Hill’s more heavily because its top-five slots are disproportionately carbohydrate rather than protein.
Further down, Iams adds brewers yeast, dicalcium phosphate, fish oil (DHA for puppy brain development), dried egg product, and carrot. Hill’s adds corn gluten meal, dried beet pulp, pork fat, dried egg product, chicken liver flavor, soybean oil, and fish oil. Hill’s gets fish oil in, but further down the list — meaning less DHA per serving than Iams delivers at position nine.
Both formulas use caramel color (Iams) or similar cosmetic additives, both use chicken by-product meal (Iams position three; Hill’s not present), and both carry extensive vitamin-mineral premixes appropriate for large- and medium-breed puppy growth. Where they diverge is the first-third of the ingredient list — the portion that drives the score.
Where Iams Smart Puppy pulls ahead
Whole chicken first. The top of the ingredient label carries the most weight. Iams leading with fresh chicken — rather than chicken meal — signals a real-muscle-meat protein base even if the meal form is more concentrated pound-for-pound. For owners reading labels, whole protein first is the signal they’re trained to look for.
DHA for brain development at a meaningful position. Iams carries fish oil at position nine, meaningfully higher than Hill’s. Puppies synthesize less DHA than adults and benefit from dietary sources during the first six months — Iams delivers a more accessible amount per serving.
Better price-to-grade ratio. Iams Smart Puppy runs about $1.70 per pound at Walmart, Chewy, and Amazon — roughly half the Hill’s Science Diet Puppy price point despite scoring 17 points higher. For puppy owners on a budget who still want to clear the C/D tier line, Iams is the pragmatic pick. Shop on Amazon →
Where Hill’s Science Diet Puppy holds its own
Veterinary-research infrastructure. Hill’s funds the largest in-house small-animal nutrition research program in the industry and employs more board-certified veterinary nutritionists than any competitor. Formula testing includes multi-year feeding trials. For owners who weigh research pedigree heavily, that infrastructure is real even if it doesn’t move the ingredient-list score.
No chicken by-product meal. Hill’s Puppy avoids the by-product meal that appears at position three in Iams. By-product meal is legitimate concentrated protein under AAFCO definitions, but “by-product” carries brand-perception weight that matters to some owners. Hill’s clean claim here is real.
Consistency across the product line. Hill’s Science Diet formulas are engineered to be digestively consistent from puppy through adult through senior — transitioning stays simple. Owners whose vet has prescribed a Hill’s product for another life stage or health need may reasonably want to keep the same brand for the puppy. Shop on Amazon →
The bottom line
If you care about ingredient-list architecture and want the better rubric score on a budget, Iams Smart Puppy is the clear pick — B/75 with whole chicken first and DHA in at position nine. If your vet has specifically recommended Hill’s for research or health-infrastructure reasons and your puppy is already on a Hill’s feeding plan, Hill’s Science Diet Puppy is not a bad food — it’s just not a B-tier food by our rubric. For premium A-tier puppy options, see our best puppy food guide.