Hill's Prescription Diet z/d Mini Food Sensitivities Dry Dog Food Original Bag review

Ingredients, as declared: Derivatives of vegetable origin, meat and animal derivatives, oils and fats (fish oil 0.9%), fruit, minerals, seeds. Protein source: Chicken liver hydrolysate (26%). Carbohydrate source: Maize starch.

Derivatives of vegetable origin lead the list, with meat and animal derivatives next and oils and fats after them, the fish oil inside that entry printed at 0.9%. Fruit, minerals and seeds finish the run. The two entries that define the diet are set out separately: chicken liver hydrolysate at 26% as the protein source, and maize starch as the carbohydrate source.

That 26% is a useful piece of labelling, since it tells you how much of the bag the hydrolysed protein actually accounts for. Alongside it, the fish oil means the recipe does not come down to a single animal source. A strict one-protein trial has to take the fish into account as well as the chicken origin of the hydrolysate.

Protein is declared at 17.6%, converting to 19.1% of dry matter, and fat at 14.4%, or 15.7% dry. Crude fibre reads 6.5% as fed and 7.1% dry, and the carbohydrate estimate reaches 52.1% of dry matter. Starch does most of the work in a food built to keep its protein list short. Energy comes to 353 kcal per 100g.

A natural antioxidant closes the panel. Above it the added minerals each carry a dose on the pack: iron 94.7mg, iodine 4.1mg, copper 11.1mg, manganese 9.8mg and zinc 147mg.

The feeding guide stops at 15kg, in keeping with the small-dog remit: 30 grams a day at 1kg, 105 grams at 5kg, 180 grams at 10kg and 245 grams at 15kg. Your vet settles where your dog sits in that range, and whether a hydrolysed diet suits him at all.

It comes in 1kg and 6kg bags, at £7.70 a kilo. Taking a 15kg dog as the basis, that is around 238 grams a day and about £1.83 a day.