Duck is used in grain-free dog food partly because it is a less common protein than chicken, which makes it a reasonable first thing to try for a dog that reacts to more everyday recipes without a vet-confirmed diagnosis yet.

Arden Grange's Grain Free Duck & Superfoods leads with duck (43% combined, from duck meat meal and fresh duck), using sweet potato and tapioca rather than grain. It adds coconut oil (1%), spirulina and chia seeds (0.1% each), and cranberry, pomegranate, blueberry, mulberry, lingonberry and rosehip extracts at 500mg/kg apiece. Protein sits at 28%.

• Available in two bag sizes
• Duck (43% combined): duck meat meal and fresh duck
• Grain free, using sweet potato and tapioca
• Protein 28%, crude fat 16%, crude ash 8%, crude fibre 3%
• Six named berry and seed extracts, each at 500mg/kg

One thing worth knowing. This is the same recipe structure as Arden Grange's grain-free chicken food, with duck as the swapped protein — useful if you are trying duck specifically because chicken did not agree with your dog, less useful if you wanted a genuinely different formulation rather than a different protein in the same shape.

Who it's for: a dog trying a novel protein because a more common one has not agreed with them, or an owner simply rotating proteins on a grain-free diet.