Short Answer: Trust the Scale, Not the Silhouette
A young Selkirk Rex is failing to thrive when her weight stalls or falls while her appetite, stools, and energy quietly worsen — even if she still looks round and teddy-like. The Selkirk's loose, plush curls create a generously padded outline that owes more to coat than to body condition, so visual checks that work on a sleek kitten fail completely here. Owners of this breed must assess by touch and by number: run your hands over her ribs and spine weekly, and weigh her on the same scale at the same time of day. A kitten can be losing condition under those curls for a fortnight before anyone would guess it from across the room.
What Your Hands Find Before Your Eyes Do
Body condition in a young Selkirk Rex is a hands-on judgement. In a thriving kitten, ribs are easy to feel under a thin, smooth layer of tissue, the spine is padded rather than knobbly, and the belly feels full and soft after meals. Failing to thrive reverses each of those: the spine's individual bumps sharpen, hip bones emerge, the neck and shoulders feel bony beneath the ruff of curls, and the abdomen may feel hollow between feeds or, conversely, tight and gassy when digestion is troubled. The coat adds its own evidence — curls that were soft, springy, and dense turn dry, wispy, and patchy-looking as protein and fat intake falls short, and the curly whiskers may break or thin.
Eating, Digestion, and the Energy Budget
A thriving young Selkirk Rex is a sturdy, patient kitten with a healthy appetite and bursts of clownish play true to the breed's easy-going nature. Failing to thrive trims all of it: she leaves food she previously finished, eats slowly as if effortful, or shows interest at the bowl and then walks away after a few mouthfuls. Stools soften, increase in frequency, or alternate with straining, and vomiting after meals may appear. Her energy contracts — play sessions shorten, she chooses the floor over climbing, and she sleeps in a tighter, more withdrawn curl away from littermate pile-ups. A kitten who consistently finishes last at the bowl and first to sleep is spending more than she is taking in.
Temperature, Hydration, and Other Quiet Warnings
Several secondary signs in a young Selkirk Rex deserve deliberate checking because her coat conceals them too. Skin elasticity is tested over the shoulder blades, where a pinch should spring back instantly; a slow return suggests dehydration. Gums should be pink and moist — pale, dry, or tacky gums are warnings. A kitten failing to thrive often feels cooler along the ears and paws and seeks heat sources persistently, because an under-fuelled body trims its thermostat. Persistent crying in a very young kitten, a weak or absent sucking reflex in one still nursing, and failure to keep up with littermates' growth milestones round out the picture of a kitten whose systems are falling behind.
When It Becomes a Vet Visit, and What to Track
Treat any weight loss in a young Selkirk Rex, a full day of refused food, repeated vomiting, watery diarrhoea, laboured breathing, or a kitten who is hard to rouse as a same-day veterinary call, and as an emergency if breathing or consciousness is involved. Young kittens carry minimal reserves, and a slow two-week slide can become a crisis in hours once appetite stops completely. Until the appointment, keep her warm, offer her familiar food in small frequent meals, and note exact figures: daily weights, amounts eaten, stool descriptions, and when her play shortened. KinsLe Pet Passport holds those weigh-ins, feeding notes, and each vet visit in a single record for a young Selkirk Rex, giving the clinic the trend line that her deceptive curls would otherwise hide.