Kitten food for British Longhair with Persians

A 3-month-old British Longhair arriving into a home with two established Persians — that's a lovely setup, and getting the kitten's nutrition right from day one is genuinely important here. Kittens have very different needs from adult cats: they need higher protein, more calories, and key nutrients like DHA, calcium, and phosphorus to support rapid bone, muscle, and brain development. This phase sets the foundation for everything that follows. To point you in the right direction — how old is the kitten exactly, do you know whether it's a British Longhair cross or purebred, and what is it eating at the moment?

Perfect — that breeder has done you a favour by starting her on Royal Canin, because it means her digestive system is already used to that formulation style. Switching within the same brand is always smoother. Now, British Longhairs are very closely related to British Shorthairs — same stocky, muscular build, same tendency to develop a broad chest and dense bone structure — so breed-specific kitten food designed for British Shorthairs will serve her extremely well. One quick question before I recommend: are you planning to feed her separately from the Persians, or do you need something that could work alongside their routine without chaos?

That's a really sensible approach, and the good news is that Royal Canin's breed-specific ranges make it easier to keep feeding distinct even when cats are eating near each other — the kibble shapes are genuinely different between lines, which helps. For your kitten, I'd go with Royal Canin British Shorthair Kitten dry food. It's designed specifically for the compact, muscular build she'll develop — higher protein to support lean muscle growth, a precise calcium-to-phosphorus ratio for her dense bone structure, and DHA from fish oil for neurological development. The kibble is a rounded shape that suits a broad muzzle, which British Longhairs share with their Shorthair cousins. It'll carry her through to 12 months when you can transition her to an adult formula. Since your Persians are on Royal Canin Persian adult — a completely different kibble shape and formula — there's very little temptation for cross-eating, which makes your multi-cat household genuinely easier to manage.

At 3 months, the Royal Canin British Shorthair Kitten bag has a feeding guide on the back based on target adult weight — for a British Longhair female, you're likely looking at an adult weight of around 4–5kg, so roughly 35–45g of dry kibble per day split across three meals at this age. Adding wet food is genuinely beneficial at this stage: it boosts hydration, which matters for kidney health long-term, and it makes the transition to a varied diet smoother. A complementary wet food like Royal Canin Instinctive Kitten in gravy (the 85g pouches) once a day alongside the dry is a clean, consistent pairing. Just reduce the dry portion slightly on days you include wet so you're not overfeeding — the bag will give you the mixed-feeding guide too.

Great choice — you're set up well. Transition her gradually over 7 days by mixing increasing amounts of the new food with the Babycat she's on now, so her stomach adjusts without any upset. At around 12 months, move her onto Royal Canin British Shorthair Adult, which slots neatly into the same brand ecosystem as your Persians. Good luck with the introduction — British Longhairs tend to be wonderfully calm cats, which should help enormously with keeping mealtimes peaceful.