The scores
Royal Canin Chihuahua: D (38/100) — Below average. Corn leads, with chicken by-product meal at #2 and wheat gluten at #3 — a plant protein booster outranking the grain sources. One of the lowest-scoring Royal Canin breed formulas.
Wellness CORE: A (90/100) — Well above average. Deboned turkey, turkey meal, and chicken meal occupy three of the top five positions. Grain-free with probiotics and chelated minerals.
A 47-point gap is among the largest we’ve measured. These products represent fundamentally different approaches to dog nutrition — one built on corn and by-products, the other on named animal proteins.
How the ingredients compare
Royal Canin Chihuahua: Corn, Chicken By-Product Meal, Wheat Gluten, Oat Groats, Brewers Rice
Wellness CORE: Deboned Turkey, Turkey Meal, Chicken Meal, Peas, Chicken Fat
The contrast is stark. Wellness CORE places three named animal proteins in its top five — deboned turkey (fresh whole meat), turkey meal (concentrated protein), and chicken meal (concentrated protein). Royal Canin places corn at #1, chicken by-product meal at #2, and wheat gluten at #3. Wheat gluten is a concentrated plant protein that artificially inflates the protein percentage without adding animal-sourced nutrition.
For Chihuahuas — tiny dogs with fast metabolisms and small stomachs — nutrient density per bite matters enormously. A corn-based formula means your Chihuahua is filling its small stomach primarily with carbohydrates rather than the protein and fat its metabolism demands.
Where Wellness CORE pulls ahead
Triple animal protein: Three named animal proteins in the top five (deboned turkey, turkey meal, chicken meal) deliver a protein profile that no amount of corn and by-product meal can match. The protein in Wellness CORE is overwhelmingly animal-sourced, while Royal Canin relies on wheat gluten to hit its protein numbers.
Grain-free, no corn or wheat: Wellness CORE eliminates corn, wheat, and soy entirely. For Chihuahuas with dental issues (overcrowded teeth are common in the breed), digestive sensitivity, or food allergies, removing these common irritants can reduce inflammation and GI distress.
Probiotics and chelated minerals: Wellness CORE includes Enterococcus and Bacillus fermentation products for gut health, plus chelated (proteinate) minerals for superior absorption. Royal Canin includes chelated minerals too, but no probiotics — a notable omission for a small breed prone to digestive issues. Shop on Amazon →
Where Royal Canin Chihuahua holds its own
The Chihuahua-specific kibble is genuinely tiny — designed for one of the smallest dog breeds in the world. Chihuahuas can struggle with standard-sized kibble, and the breed-specific shape helps. This is a real functional advantage that Wellness CORE’s general-purpose kibble doesn’t address (though Wellness does offer small-breed formulas).
GLA safflower oil supports skin health, and fructooligosaccharides act as a prebiotic. The formula also includes DL-methionine, which can support urinary health. These breed-relevant additions show formulation thought, even if the base ingredients don’t match.
Price may also be a factor — Royal Canin Chihuahua can be found for less per pound, though the per-serving cost difference is small given how little a Chihuahua eats. Feeding a 5-pound dog premium food costs less per month than almost any other breed. Shop on Amazon →
The bottom line
Wellness CORE is the clear winner at A/90 vs D/38 — a 47-point gap that reflects a fundamental difference in ingredient philosophy. For Chihuahua owners, the cost of feeding a tiny dog premium food is minimal (a bag lasts months), making the upgrade to Wellness CORE one of the most affordable quality improvements available.
Royal Canin Chihuahua’s tiny kibble is a genuine advantage, but a D-grade formula with corn first and wheat gluten at #3 is hard to justify when B-grade alternatives exist at similar price points. Read our full reviews of Royal Canin Chihuahua and Wellness CORE for the complete analysis.