What to Feed a Newborn Rabbit: Formula, Volumes by Age and Honest Odds

If the doe has died or abandoned the litter, your first move is not a syringe — it is another lactating doe. Fostering beats hand-rearing by a wide margin, and the veterinary literature is blunt about the alternative: kits can be hand-reared, but mortality is high. Spend five minutes on the fostering question before you mix a drop of formula.

The window is narrow. The MSD Veterinary Manual describes moving kits out of the nest box in the first three days and giving them to a doe of roughly the same kindling date with a smaller litter; mixed among her own kits and dusted with her fur, they are generally accepted. FAO sets the same limits: no more than three kits per foster mother, an age gap under 48 hours, and the transfer within five days of kindling.

If no foster doe exists, hand-rearing is what is left — but be realistic, because the Rabbit Welfare Association puts it plainly: raising orphaned or rejected kits is extremely difficult. One check first. A nest of naked kits in a shallow scrape in your lawn is a wild litter, not an abandoned one, and in most countries taking it into care without a permit is illegal. See our guide to newborn wild rabbit care before you touch it.

• A second doe that kindled within 48 hours of this litter? If yes, foster.
• Her litter smaller than her nipple count (most medium does have 8–10)? She has room.
• Kits under five days old? Beyond that the transfer usually fails.
• Split a litter across several does rather than loading three-plus onto one.
• No foster doe: warm the kits first, then hand-feed — never the reverse.

A cold kit cannot digest milk, and feeding one is how well-meaning finders kill kits that would otherwise have lived. The MSD Veterinary Manual's neonatal chapter gives the mechanism: hypothermia induces ileus — the gut stops moving — and regurgitation and aspiration can result. Milk poured into a stalled stomach is not absorbed.

So the rule for orphaned mammals is unambiguous: hypothermia and dehydration must be corrected before feeding. Aim for a body temperature of at least 36 °C (97 °F) before any milk goes in, and rewarm slowly, over 30 to 60 minutes, because fast rewarming causes peripheral vasodilation and worsens dehydration.

Newborn rabbits are helpless at this: they cannot thermoregulate until about day seven, are born naked, gain their first hair only on day two or three, and cannot curl up to conserve heat. FAO's account is worth reading twice — kits hold their temperature only if the surrounding air is at least 28 °C, ideally 30–32 °C, and only with littermates to huddle against; a kit can die of cold 10 cm from the group. In practice: a heat mat on low under half the container, a fleece nest, and a lid.

• Target body temperature before feeding: at least 36 °C (97 °F).
• Rewarm over 30–60 minutes, not in a few minutes.
• Nest air: 28–32 °C (82–90 °F), with a cooler zone the kit can crawl to.
• Kits cannot thermoregulate until roughly day 7 — the heat has to come from outside.

Doe milk is one of the richest produced by any mammal, and that is the problem with substitutes. Pooling twenty published analyses, a World Rabbit Science review puts mature rabbit milk at 12.9 g of fat and 12.3 g of protein per 100 g, with under 2 g of lactose — against cow's milk at roughly 4% fat, 3.5% protein and 5% lactose.

Kitten milk replacer mixed to the label is aimed at a cat and lands well below that. MSD's orphan-wildlife chapter closes the gap by concentrating the powder rather than adding random fats: 2 parts KMR powder to 1 part water by volume — roughly double normal strength — with a pinch of acidophilus. Its alternatives are 1:1 Esbilac powder to water, or 4:1:4 Esbilac powder to heavy cream to water: raise the fat, keep the sugar low.

The rabbit chapter also accepts goat milk replacer, a commercial rabbit-rearing formula, or half a cup of evaporated milk with half a cup of water, one egg yolk and a tablespoon of corn syrup. The near-absence of lactose in rabbit milk is one reason over-diluted, over-sweetened home mixes give kits diarrhoea. Mix fresh, warm to body temperature, and never feed plain cow's milk.

• Target to beat: about 12.9% fat, 12.3% protein, under 2% lactose.
• KMR powder to water at 2:1 by volume, plus a pinch of acidophilus.
• Or Esbilac powder to water at 1:1, or powder : heavy cream : water at 4:1:4.
• Mix fresh each feed, warm to body temperature, discard leftovers.

The thing a syringe cannot deliver is the doe's microbiome, and this is where hand-reared kits quietly fail at weaning rather than in week one. A rabbit runs on caecal fermentation: the soft faeces it re-ingests supply microbial protein, all the B vitamins it needs and volatile fatty acids. A kit is not born with that community.

One route is easy to overlook. Work on caecal microbiota establishment names, as a concrete microbial source, the faecal pellet the doe deposits in the nest while nursing and the kits then eat. Chewing is functional from day 10 to 13, well before kits take real solid feed. An orphan in a plastic tub gets none of that, and MSD's own orphan formula acknowledges the gap by adding acidophilus. Experienced keepers go further, adding a trace of fresh caecotrophe from a healthy adult of the same herd.

Be clear about the evidence grade, because nobody else here is. The seeding route is published; a survival benefit from deliberately inoculating hand-reared kits is not. Figures passed between breeders — survival going from roughly 30% to roughly 70% — are practitioner experience, not a controlled trial. There is a real downside too: faeces carry coccidia, so use only a demonstrably healthy, unmedicated adult from your own herd, a trace amount, and stop at the first loose stool.

• Published: the doe's faecal pellet in the nest is a microbial source for kits; MSD adds acidophilus to orphan formula.
• Practitioner experience only: that adding a trace of fresh caecotrophe lifts hand-reared survival.
• Risk: faeces can carry coccidia — use a healthy, unmedicated adult from your own herd, or skip it.

Feed by weight, not by eye. The anchor is from MSD: a neonatal rabbit's stomach holds 100–125 mL per kilogram of body weight, about 10–12% of the kit. A practical working figure is roughly 10 mL per 100 g per feed, twice in 24 hours, starting at half that on day one. The same manual's rabbit chapter gives half a teaspoon to two tablespoons per feed depending on age — 2.5 to 30 mL — which brackets the table below.

Turning that into day-of-age guidance needs typical kit weights, and those are published. Across 1,696 kits of the ITELV2006 line, mean individual weight ran 54 g at birth, 86 g at 5 days, 109 g at 7 days, 192 g at 14 days, 279 g at 21 days, 409 g at 28 days and 603 g at 35 days. Weigh your own kit — MSD gives a domestic birth-weight range of 30–80 g by breed — and where weight and day of age disagree, follow the weight.

The arithmetic checks out against what a doe delivers. FAO puts daily milk at 30–50 g for the whole litter in the first two days, rising to 200–250 g by the end of week three; across eight kits that is 4–6 g each per day at the start and 25–31 g at three weeks. The check that it is working is daily weight gain, and MSD advises daily weights for the first two weeks: expect about 6 g a day over the first five days, 11–12 g through weeks two and three, and 19–28 g after that. No gain in 24 hours means the volume, temperature or formula is wrong. If you log litters in RabbitBreeder, put the daily weights on the kit's record.

• Day 0–3 (about 50–70 g): 2–3 mL per feed, twice daily
• Day 4–7 (about 70–110 g): 4–7 mL per feed, twice daily
• Day 8–14 (about 110–190 g): 7–12 mL per feed, twice daily
• Day 15–21 (about 190–280 g): 12–17 mL per feed, twice daily
• Day 22–28 (about 280–410 g): 17–25 mL per feed, twice daily, plus hay and pellets
• Day 29–35 (about 410–600 g): 25–30 mL, tapering to one feed as solids take over

Feed twice a day. This is the single point on which most of the first page of search results is wrong, and getting it wrong causes the two things that kill hand-fed kits: aspiration and gut overload. MSD is explicit — kits should be fed only every 12 hours, to avoid overfeeding and to mimic the natural feeding behaviour of the doe.

The reason is that rabbits are not cats. FAO is categorical: the doe sets the number of feeds, and it is once in 24 hours; suckling alone will not trigger the oxytocin release. MSD's rabbit chapter allows once or twice daily, each bout under three minutes, and the Rabbit Welfare Association tells worried pet owners the same — the milk is very rich, so kits only need feeding once or twice a day. Advice modelled on kittens produces a kit handled a dozen times a day, chilled at every handling, and overfilled.

There is one honest exception. MSD notes that while healthy neonates are fed twice a day, up to four feeds may be needed — for a weak, dehydrated or underweight kit, or where a tube feed has had its volume cut. Needing four beyond the first day or two is a signal to get veterinary input.

• Default: two feeds per 24 hours, roughly 12 hours apart.
• Up to four smaller feeds only for a weak, dehydrated or tube-fed kit.
• Never feed on a 2–3 hour kitten schedule: it causes overfilling, chilling and aspiration.

Use a slip-tip syringe — the plain kind with no locking collar — which is what MSD specifies for orphaned rabbits. A 1 mL syringe suits kits under a week; move up to 3 mL and then 5–10 mL as volumes grow. Never use a needle, and be sceptical of pet nursing bottles: the flow is too fast for a kit's weak swallow.

Hold the kit upright or leaning slightly forward, resting on its front, head level and nose pointing down rather than up. Never feed a rabbit on its back. Introduce the tip at the corner of the mouth, deliver one drop at a time, and let the kit swallow between drops — the kit sets the pace, not the plunger. If milk appears at the nostrils, stop, tip the head gently down to drain, dry the face and wait: aspiration pneumonia kills more hand-fed kits than starvation does.

Where a kit will not suck, MSD's guidance is to tube-feed with the volume cut by 30% and an extra feeding added — but passing a tube into a 50 g rabbit is a veterinary procedure, not a first attempt. Finish every feed by stimulating elimination: kits cannot urinate or defecate unaided in the early days, and the doe triggers it by licking. Stroke the perineal area gently with warm, moist gauze after each feed until the kit eliminates without help.

• Slip-tip syringe, no needle: 1 mL under a week, 3 mL and up thereafter.
• Kit upright on its front, head level, nose down — never on its back.
• One drop at a time; the kit swallows, then you deliver the next.
• Milk at the nostrils: stop, drain, dry, wait. Do not push on.
• Tube feeding: volume cut by 30% plus an extra feed — a vet's job.
• After every feed, stroke the perineal area with warm moist gauze.

Eyes and ears open around day 10 and chewing becomes functional between days 10 and 13, but real solid intake starts later. FAO puts the onset of solid feed at 18 to 20 days, and by day 30 the doe's milk supplies no more than 20% of daily intake. Copy that schedule: offer solids from about day 14, and expect nibbling rather than eating for the first week.

Put out soft leafy hay — alfalfa or a fine grass hay — and a small amount of pellet formulated for growing rabbits, which MSD specifies at 16% total protein and 14–16% fibre. Keep pellets measured and hay unlimited: low-fibre diets raise the incidence of intestinal problems including enterotoxaemia, and weaning is when a young gut is most vulnerable. Add water in a shallow, heavy dish from the same day — rabbits drink about 120 mL per kg per day, and take significantly more from an open bowl than a sipper bottle.

Taper the milk as solids rise and finish between four and six weeks; FAO's commercial benchmark is weaning once liveweight passes about 500 g, at roughly 26 to 30 days. What not to offer: muesli-style mixes, which the RSPCA advises against because they drive selective feeding, dental disease and obesity, and fruit or high-sugar vegetables, of which MSD names carrots explicitly.

• Day 14: put soft alfalfa or fine grass hay and a few growing-rabbit pellets in reach.
• Day 18–20: genuine solid intake begins; keep milk feeds going alongside.
• Pellets for growth: about 16% protein, 14–16% fibre; hay unlimited, pellets measured.
• Shallow open water dish from day 14 — rabbits drink far more from a bowl than a bottle.
• Full wean at 4–6 weeks. No muesli mixes, no fruit, no carrots.

There is no published table giving the survival of a hand-reared domestic kit by its age at rescue. If you find one quoted with confident percentages, it is invented. What exists is a set of figures that measure adjacent things, and knowing which is which stops you from either despairing or expecting too much.

Start with the baseline where the doe does the work: FAO reports birth-to-weaning mortality around 20% in European rabbitries and notes that getting below 12% is very difficult. MSD says only that hand-reared kits can be raised but mortality is high — deliberately, no number. What does have hard numbers is birth weight. Across 1,696 kits, each additional gram of birth weight raised the probability of surviving to weaning by 8–10%, and each extra kit in the litter lowered it by 5–9%.

The often-quoted claim that fewer than 10% of orphans survive a week is about wild cottontails and comes from rehabilitation practice, not a controlled study. Cottontails are a different genus — 30–40 g at birth, eyes open at 7–10 days, weaned at three to four weeks. The largest peer-reviewed dataset, 1,256 orphaned eastern cottontails over six years, is worth reading for one finding: kits treated by the finder before presentation were significantly more likely to die, while body weight and dehydration did not predict outcome. For a breeder the useful response is measurement — record birth weights, daily weights, and which litters lost kits and when. Litter and mortality logs in RabbitBreeder exist for that.

• Doe-reared baseline: about 20% birth-to-weaning mortality; under 12% is hard to reach.
• Each extra gram of birth weight: 8–10% better odds of reaching weaning.
• The 'under 10% survive a week' figure is cottontail-specific and comes from practice, not a trial.
• In 1,256 orphaned cottontails, prior treatment by the finder predicted a worse outcome.