Someone Just Handed You a Box of Newborn Kittens. Here's What to Do First.

It's June, which means it's kitten season, which means sooner or later someone is going to find you. A neighbor, a coworker, a stranger who got your number from someone who got it from someone else. They'll be holding a box, or a shoebox, or a folded-up sweatshirt, and inside it will be a litter of newborn kittens with their eyes still closed and no mother anywhere.

Bottle babies are the most fragile animals most rescuers will ever handle. A neonatal kitten can be fine in the morning and gone by dinner. But they are not impossible, and the things that save them are not complicated. They're just relentless. Here's the order of operations for the first critical days.

Warm First. Always.

This is the rule that matters more than any other, and the one most people get wrong because their instinct is to feed a hungry-sounding kitten immediately.

Do not feed a cold kitten. Hypothermia is the number one killer of newborn kittens, and a cold kitten's digestive system shuts down — feeding one can cause the formula to sit in the gut undigested or be inhaled into the lungs, which is often fatal.¹ Newborns can't shiver until about two weeks of age and can't regulate their own body temperature until around four weeks.² Out in the world without their mother, they get cold fast.

So before anything else, get them warm. The nest should sit at roughly 85–90°F.¹ Use a heating pad set to low under half of the box (so a kitten can crawl off it if it gets too warm), a microwavable heat disc, or a hot water bottle wrapped in a towel. Warm them slowly — over one to three hours, not instantly. Rewarming a hypothermic kitten too fast causes its own problems.² A kitten is warm enough to feed when its ears, pads, and mouth are warm to the touch, not cool.

While they warm up, you have time to get the rest of your supplies together.

Get the Right Formula (and Never Cow's Milk)

The single most common mistake well-meaning finders make is reaching for the fridge. Cow's milk will give a kitten diarrhea and dehydrate it, which in an animal this small is dangerous on its own.³

What you need is a commercial kitten milk replacer — KMR is the most widely available brand. Powdered formula mixed fresh is generally preferable to canned, but in an emergency, canned will do until you can get to a pet store. Warm the formula to about body temperature (roughly 100°F) by standing the bottle in a cup of warm water, and test a drop on your wrist the way you would for a human baby.³ Cold formula, like a cold kitten, is a problem.

You'll also want a kitten nursing bottle with a nipple cut so a drop forms when you turn it upside down and gently squeeze — not a stream. And buy a cheap digital kitchen scale that reads in grams. It is the most important diagnostic tool you own, and we'll come back to it.

How Much, How Often

Feeding frequency is driven by age, and for the youngest kittens it is genuinely around the clock.

For the first two weeks, plan on feeding every two to three hours, day and night.⁴ Yes, that includes 3 a.m. From two to four weeks you can stretch to roughly every four to five hours. By four weeks you're moving toward four feedings a day as solid food enters the picture.⁴

For amount, a useful rule of thumb is about 2 tablespoons (30 ml) of formula per 4 ounces (115 g) of body weight per day, divided across all the feedings in that day.⁵ A newborn might take only a few milliliters per feeding; let the kitten tell you when it's done. You want a kitten that's full and content, with a slightly rounded belly — not a tight, bloated one. If a kitten won't eat, isn't gaining, or is weak, it needs to be seen, and in the meantime it may need feeding more often to avoid low blood sugar.⁴

How to Feed Without Hurting Them

Position is everything, and getting it wrong leads to aspiration pneumonia — formula inhaled into the lungs — which kills kittens this small.⁶

Feed a kitten belly-down, the way it would nurse from its mother, or upright against your hand. Never feed a kitten on its back like a human infant.⁶ Tilt the bottle to about a 45-degree angle, keep a slight tension so the kitten works for it, and never squeeze formula into its mouth.⁶ Let the kitten suckle at its own pace. If you see bubbles at the nose or hear it sputter, stop, lower the head, and let it clear.

After feeding, burp the kitten gently against your shoulder or with a soft pat on the back, just as you would a baby.

Make Them Pee and Poop

Kittens under about three weeks can't eliminate on their own. The mother normally licks them to stimulate it; without her, that job is yours.

Before and after each feeding, take a warm, damp cotton ball or soft cloth and gently rub the genital and anal area until the kitten urinates and, at least once a day, defecates.⁷ They should pee at nearly every stimulation and poop at least daily. One caution from shelter-medicine guidance: don't scrub directly and repeatedly on the anus, which can ulcerate the tissue — wipe gently and bilaterally instead.⁷ Keep doing this until around three weeks of age, when they start managing on their own.

Weigh Every Single Day

If you do nothing else on this list well, do this. A gram scale and a daily number is the closest thing you have to an early-warning system.

Healthy newborns weigh roughly 100 grams at birth and should gain about 10 grams a day, every day.⁸ Weigh each kitten at the same time each day — before a feeding is easiest — and write the number down. A kitten that stops gaining, or loses weight even for a day, is the first and often only sign you'll get that something is wrong, hours before it looks visibly sick. Catching a flat weight curve on Tuesday instead of Thursday is frequently the difference between a vet visit and a death.

This is also where a little structure pays off. A litter of five bottle babies means five weights a day, multiple feeds each, stimulation logs, and any meds — across however many people are sharing overnight shifts. A shared record (a notebook works; a tool like Pawsies that lets every volunteer log weights and feedings against each individual kitten works better) means the person taking the 6 a.m. shift can see at a glance that kitten #3 didn't gain yesterday and ate poorly at 2 a.m. Scattered sticky notes can't tell you that.

When Weaning Starts

Around four weeks, kittens can begin learning to eat on their own. Offer a thin gruel of warm canned kitten food mixed with formula in a shallow dish, and keep bottle-feeding alongside it while they get the hang of it.⁹ Weaning is gradual and usually wraps up by eight to ten weeks.⁹ Don't rush it — a kitten pushed off the bottle too early simply eats less and stops growing.

Know When It's Above Your Pay Grade

Raising bottle babies is hard, and not every kitten can be saved no matter how perfectly you do everything. Get a kitten to a vet promptly if it is cold and won't warm up, won't eat, is losing weight, has diarrhea, is gasping, or has formula coming from its nose. None of that is a personal failure. Neonatal care is unforgiving, and the people who are best at it are the ones who ask for help early.

If you're not set up for around-the-clock feeding, that's worth knowing about yourself before kitten season, not at 2 a.m. with a fading kitten. Line up a bottle-baby-experienced foster, your local shelter's neonatal program, or an experienced colony volunteer now, so you have somewhere to turn when the box shows up. Because in June, it will.