Chapel Farm Invest 'N' Digest Grain Free review

The two recipes keep step on our scale, both of them inside our Good band and matching the typical adult dry food. The duck's edge shows in its pillar readings, where protein and processing and nutritional balance both come out Good against the salmon's Average, with value in step with each recipe's overall placing. Neither is chasing headlines; both are middle-order foods with a clear digestive brief.

Ingredients, as declared: Salmon (30%, of which dried salmon 17%, hydrolyzed salmon 7%, salmon gravy 6%), sweet potatoes (17%), potato flakes (17%), peas (17%, salmon oil (7%), potato protein, dried beet pulp, dried chicory (0.5%, a natural source of FOS and inulin), minerals, yeast hydrolysate (a natural source of MOS and beta glucans), Yucca schidigera.

The original recipe does something genuinely uncommon: from the salmon at 30% down through potato protein and beet pulp, no second animal appears anywhere. That salmon is supplied dried at 17%, hydrolysed at 7% and as gravy at 6%, working forms rather than fresh fillet, and dried fish holds its protein through cooking far better than fresh would.

The duck recipe reads similarly but is built differently: duck at 34% splits into 26% dried and 8% fresh, then poultry fat, vegetable stock and a 0.5% ration of salmon oil follow. Those last entries are why it cannot make the single-animal claim its sibling can.

Sweet potato, potato flakes and peas at matching shares carry the starch in both recipes. Estimated carbohydrate finishes at 46.9% and 44.6% of dry matter, either side of the 46.2% typical for adult dry food. This is a carbohydrate-forward construction, softened by the quality of the sources.

The digestive brief is delivered through dried chicory at 0.5%, a natural source of FOS and inulin, and a yeast hydrolysate bringing MOS and beta glucans, both prebiotics that feed the gut's resident good bacteria. Beet pulp adds the gentle fibre such recipes lean on.

The additive panel is dosed in print on both bags, with taurine at 1000 mg per kilo and L-carnitine included, at 100 mg in the salmon and 500 mg in the duck. Salmon oil at a full 7% gives the original recipe a generous omega 3 allowance, the kind that tends to show up in skin and coat.

This is the fish-only half of the pair, the bag to buy when one animal in the bowl is the whole point. Its label also extends to senior dogs, and salmon oil at 7% makes it the richer of the two for omega 3s.

Both recipes are £3.33 a kilo and come in 12kg bags.

Day to day, a 15kg adult dog in moderate condition would need about 243 grams of the salmon recipe (£0.81 a day) or 235 grams of the duck (£0.78). Those figures are built on the standard maintenance estimate of around 840 kcal (110 × bodyweight^0.75) and on label energy values that are themselves estimates.