The Direct Answer for a Devon Rex
It is not safe for a Devon Rex to live on food made for other kinds of pets, although a single snatched mouthful of the dog's dinner is a lapse, not an emergency. Cats are obligate carnivores with non-negotiable dietary requirements: they must get taurine, preformed vitamin A and certain fatty acids directly from their food, and they need a higher protein level than dogs do. Dog food is formulated for an animal that can manufacture or manage without several of those things, so a cat fed it regularly is being slowly undernourished even while his stomach feels full. Rabbit, guinea pig and bird foods are further still from a cat's needs, being largely plant-based, and ferret food, while meaty, is balanced for a different animal and often too rich for everyday cat feeding.
Why a Devon Rex Shows the Problem Sooner
The Devon Rex runs a lean, warm, high-energy body on a fine, wavy coat that offers little insulation, and many Devons have notably touchy stomachs. A diet short on the nutrients cats require can show up in this breed as a coat that loses its wave and density, dull skin, fading energy in a cat who is normally a clownish livewire, and digestive looseness that a sensitive Devon gut tolerates badly. These changes creep in over weeks, which is exactly why regular cross-feeding is the danger rather than one stolen bite. A Devon who raids the dog bowl daily is quietly replacing cat-balanced meals with food that cannot support him, and because he is small-framed, the shortfall represents a bigger share of his total intake than it would in a large cat.
What to Do When Pets Share a Home
Feed each species its own food, in its own place, at set times, and lift bowls afterwards rather than leaving them down for cross-grazing. A stair gate, a door propped to cat width, or feeding the cat up on a counter or utility surface keeps a Devon safely away from the dog's bowl while letting him eat in peace; microchip-activated feeders solve the problem neatly in determined multi-pet homes. Store the bags separately and label scoops, because the commonest route to the wrong food is a helper or family member filling every bowl from whichever bag is open. If your Devon has eaten a lot of another pet's food in one go, watch for vomiting or diarrhoea and mention it to your vet if it persists beyond a day or he goes off his own food. Keep his water fresh and his cat food consistent rather than swapping brands to compete with the stolen flavour.
Keeping Every Feeder on the Same Page
Most cross-feeding in a busy home is accidental: a sitter assumes pet food is pet food, or a child helpfully tops up the cat from the dog's sack. Written feeding instructions are the fix, naming the exact food, the amount and the bowl for your Devon, and stating that nothing else is a substitute even if his own bag runs out; the correct response to an empty cat bag is a trip to replace it or a call to you, not improvisation. If he must stay with friends who keep other animals, send his food with him in labelled daily portions. With KinsLe Care Teams, that instruction lives on your Devon Rex's care plan where every assigned feeder sees it before they serve a meal, which turns a rule everyone meant to remember into one the routine itself enforces.