Hill's Prescription Diet z/d Skin/Food Sensitivities Dry Dog Food
- Veterinary Diet
- Veterinary Diet
- Bag
- 1
- Better rated than 72%
- More reviewed than 90%
A targeted option for dogs with a vet-confirmed food sensitivity or skin condition, built around hydrolyzed protein rather than novel-protein or grain-free marketing.
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How it ranks among the 50 veterinary diets we track
4.7★ across 1,600 Amazon ratings, Bayesian-smoothed toward the category average.
1,600 Amazon ratings, weighted on a log scale so huge counts don't drown everything.
1,000+ bought on Amazon last month.
Brand identity, imagery, description and spec coverage.
The ProductDome score is separate from the Amazon rating shown above: it combines the Bayesian-smoothed Amazon rating with evidence volume, tracked demand, and data quality across the 50 veterinary diets we track - how the scorecard works · full veterinary diets data report. Confidence: high - strong rating volume and complete data.Last refreshed Aug 4, 2026. Data-computed, not a hands-on test. Compiled by the ProductDome Research Team.
Overview
Hill's Prescription Diet z/d is a hydrolyzed chicken protein dry dog food formulated for dogs with food sensitivities and skin issues, sold here in a 25 lb bag.
Hydrolyzed protein means the chicken protein is broken into fragments small enough to avoid triggering an allergic or sensitivity response, which is the core mechanism behind Prescription Diet z/d rather than simply being a limited-ingredient food. Hill's lists it under Veterinary Diet, and Amazon's ranking of 4 in Veterinary Diet Dog Food reflects its position within that prescription-style category. As with any Hill's Prescription Diet product, confirm with your vet whether your dog's specific condition calls for this formula.
- Hydrolyzed chicken protein formula
- 25 lb bag size
- Formulated for skin and food sensitivities
- Includes ActivBiome+ digestion support
Who it's for
Fits dogs diagnosed with food sensitivities, allergies, or chronic skin and coat issues where a vet has recommended a hydrolyzed protein diet. Not intended as a general everyday food for dogs without a diagnosed sensitivity.
Strengths and trade-offs
Drawn from this product's published specifications.
- Hydrolyzed protein targets food sensitivities directly
- Formulated for skin and coat issues
- 25 lb bag suits ongoing feeding for larger dogs
- Positioned as a veterinary diet, best used under vet guidance rather than as a general food
- Veterinary-exclusive formulas often cost more than standard dry food
Performance notes
The hydrolyzed chicken protein is processed so the immune system doesn't recognize it as an allergen, which is the mechanism behind the skin and digestive benefits Hill's markets for this line. The included ActivBiome+ digestion component is aimed at supporting gut health alongside the allergy-relief function.
Specifications
| Brand | Hill's |
|---|---|
| Model | 8439 |
| Dimensions & fit | |
| Item Weight | 25 pounds |
| Package Size Name | 25 Pound |
| Dog Breed Size | All |
| Capacity & performance | |
| Age Range Description | Adult |
| Included components | |
| Unit Count | 25 pounds |
| Included Components | adult-dog-food |
| Other details | |
| Animal Food Diet Type | Veterinary Diet |
| Container Type | Bag |
| Number Of Items | 1 |
| Manufacturer | Hill's Pet Nutrition |
| Manufacturer Part Number | 8439 |
| Model Number | 8439 |
| Specific Uses For Product | Allergy Relief, Skin and Coat |
| Occasion | Birthday |
| Target Species | Dog |
| Product Benefits | Promotes digestive health and firm stools |
| Upc | 616174582367 648676233096 052742843902 638932998586 |
| Customer Reviews | {'ratings_count': '1,630', 'stars': '4.7'} |
| Additional Features | Manages food sensitivities, highly hydrolyzed proteins, ActivBiome+ Digestion |
| Breed Recommendation | All Breed Sizes |
| Recommended Uses For Product | Skin and Coat, Food Allergies |
| Allergen Information | Chicken Meat |
| Item Form | Dry Food |
| Asin | B003V5HNHE |
| Special Ingredients | protein-rich |
| Best Sellers Rank | #3,786 in Pet Supplies (See Top 100 in Pet Supplies) #4 in Veterinary Diet Dog Food #274 in Dry Dog Food |
| Flavor | Chicken |
| Item Type Name | z/d Skin/Food Sensitivities Dry Dog Food |
Other Hill's veterinary diets
How it compares
This product against the closest alternatives we track in veterinary diets.
| Product | Amazon rating | Ratings | ProductDome score |
|---|---|---|---|
| Hill's Prescription Diet z/d Skin/Food Sensitivities Dry Dog FoodThis product | 4.7 / 5 | 1,600 | 4.4 / 5 |
| Pro Plan Veterinary Diets Purina UR Urinary Ox/St Canine Formula Dog Food Dry KibblePro Plan Veterinary Diets | 4.6 / 5 | 453 | 4.1 / 5 |
| Royal Canin Veterinary Diet Canine Hepatic Adult Dry Dog FoodROYAL | 4.7 / 5 | 538 | 4.1 / 5 |
| Purina Pro Plan Veterinary Diets HA Hydrolyzed Protein Dog Food Dry Vegetarian FormulaPurina | 4.4 / 5 | 221 | 4.0 / 5 |
| Blue Buffalo Natural Veterinary Diet W+U Weight Management + Urinary Care Dry Dog FoodBlue | 4.6 / 5 | 179 | 3.9 / 5 |
Similar veterinary diets from other brands
Questions about the Hill's 8439
Common buyer questions answered straight from the product spec data - no fluff, no "it depends".
What makes Hill's z/d different from a regular dry dog food?
The chicken protein is hydrolyzed, broken into small fragments meant to avoid triggering food sensitivity reactions.
Does this require a vet's recommendation?
It's part of Hill's Prescription Diet line, so it's intended for dogs with a diagnosed sensitivity or skin condition, best used under veterinary guidance.
What bag size is this?
This listing is the 25 lb bag.