Rabbits and cold: what actually kills them in winter, and the checks that prevent it

Quick answer

A healthy, acclimatised, well-housed rabbit copes with cold far better than most owners expect. The things that kill it in winter are wet, wind and an empty water bowl.

Rabbits are not fragile in the cold. A healthy adult that has grown a winter coat, stays dry, is out of the wind and has unlimited hay handles low temperatures well.

What kills rabbits in winter is rarely the temperature by itself. It is a frozen water supply that stops the rabbit drinking, which stops it eating, which stops the gut. Gut stasis can kill a rabbit within a day or two, and it starts with an empty bowl.

• Check water twice daily in freezing weather, and check that it flows, not just that the bottle looks full.
• Never move a rabbit that has been living indoors into an outdoor hutch during autumn or winter.
• Wet plus cold is the dangerous combination. A dry rabbit in a draught-free hutch is in a different situation from a damp one.
• A rabbit that has stopped shivering and has gone quiet is not settling. It is getting worse.
• Never house rabbits in a garage that a car is used in. Exhaust fumes kill rabbits.

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A cold, quiet, unresponsive rabbit is an emergency, and rewarming must be slow.

Rabbits do not hibernate. There is no version of a healthy rabbit that becomes sleepy and unresponsive in the cold. Shivering that stops as a rabbit becomes colder is a sign of deterioration, not recovery.

Move the animal somewhere warm but not hot, wrap it in dry towels, and warm it gradually over an hour or more using your own body heat or a covered warm water bottle it can move away from. Do not use a hairdryer, a direct heat pad, an uncovered hot water bottle, hot water immersion or a radiator.

Rapid rewarming of a severely chilled animal can trigger a dangerous drop in blood pressure and a fall in blood sugar. Get to a vet while you warm the rabbit, not after.
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Decide in 60 seconds

How rabbits actually cope with cold

A wild rabbit lives in a burrow, where the temperature is far more stable than the surface, and it does not experience wind or rain directly. It also has a companion group, a winter coat and constant access to fibrous food.

Domestic rabbits keep the physiology and lose the burrow. Give them the equivalents and they cope well.

The coat.
Rabbits grow a denser winter coat over several weeks, cued by shortening day length. This is why a rabbit that has spent autumn in a heated room has no winter coat by the time the weather turns, and why a mid-winter move outdoors is dangerous even for a healthy adult.

Fermentation heat.
A rabbit's caecum is a large fermentation chamber, and fermentation produces heat continuously. A rabbit eating unlimited hay has an internal heat source running all day. A rabbit that has gone off hay loses it, which is one of the reasons a rabbit that stops eating in winter deteriorates faster than one that stops eating in summer.

Behaviour.
Rabbits huddle, dig into deep bedding, and choose sheltered spots. Give them the ability to do all three and they regulate themselves.

Circulation to the ears.
Rabbits shed heat through their ears. In cold weather, blood flow there reduces, which is why cold ears alone in a bright, eating rabbit are not an alarm on their own. Cold ears together with cold feet and a subdued rabbit are a different matter.

What actually goes wrong in winter

Frozen water.
The single most important item on this list. Bottles freeze at the spout first and the ball seizes, so the bottle can be three quarters full and delivering nothing. Bowls ice over. A rabbit that cannot drink reduces its food intake within hours, and reduced food intake in a rabbit means slowed gut movement.

Use heavy ceramic bowls rather than relying on bottles, check twice daily by actually operating the bottle or breaking the ice, and refill with lukewarm rather than cold water so it takes longer to freeze.

Damp.
Wet fur loses almost all its insulating value, because the insulation comes from trapped air. A rabbit that is damp from rain blowing in, from a leaking roof, from condensation or from soiled bedding is in a completely different situation from a dry one at the same temperature.

Draughts and wind.
Still cold air is manageable. Moving air strips heat away far faster. A hutch with a wind blowing through it is dangerous at temperatures the same rabbit would handle comfortably in a sheltered position.

Condensation and poor ventilation.
The instinct to seal a hutch up completely creates its own problem: moisture and ammonia build up, the bedding becomes damp, and respiratory disease follows. Rabbits need shelter from wind and rain with air still moving.

A sudden move.
Indoors to outdoors, or a change of housing, in cold weather. Acclimatisation takes weeks and cannot be compressed.

Reduced exercise.
Rabbits move less in bad weather. Less movement means slower gut, weight gain in some and loss of condition in others, and more time sitting on damp flooring, which causes sore hocks.

Being alone.
A single rabbit has no one to huddle with and is also more prone to the stress and inactivity that make everything else worse.

Predators.
Foxes and other predators are hungrier in winter and press harder at hutches. Rabbits can die of the stress of a predator at the wire without ever being touched.

Garages.
A garage seems like an obvious solution and is one of the most dangerous. Carbon monoxide and other exhaust components from a car started in an enclosed space are lethal to a rabbit. A garage is only acceptable if no vehicle ever runs in it.

Weigh weekly through winter. Condition loss under a thick winter coat is close to invisible by eye.

Recognising hypothermia, stage by stage

Early.
The rabbit seeks shelter, tucks into bedding, sits hunched with the fur fluffed and the feet tucked under. Ears feel cold. It is still eating, still responsive.

Moderate.
Shivering. Both ears and feet feel cold. The rabbit is quieter than usual, slower to respond, and eating less. This is the stage where intervention is straightforward and effective.

Severe.
Shivering stops. This is the critical point and it is regularly misread as the rabbit settling. The animal becomes floppy, unresponsive or semi-conscious, the mouth and gums feel cold, breathing is slow and shallow, and the heart rate falls.

Rewarming.
Slow and gentle. Dry towels, a warm room but not a hot one, body contact, or a warm water bottle wrapped in towels that the rabbit could move away from if it were able to. Aim for gradual over an hour or more. Do not use direct heat sources.

The reason for the caution is real. Warming the skin and limbs rapidly opens peripheral blood vessels and drops blood pressure while the core is still cold, and severely chilled animals are frequently also hypoglycaemic. This is why severe hypothermia is a veterinary case rather than a home one.

What else makes a rabbit hunched and quiet in winter

Cold is one explanation among several, and they overlap.

Gut stasis.
No droppings or markedly fewer, a hunched posture, grinding teeth, refusing food. It is the commonest rabbit emergency and cold weather is a strong trigger through reduced drinking and reduced movement.

Dental pain.
A rabbit with molar spurs eats less hay, produces less fermentation heat and loses condition. Winter often unmasks a dental problem that was borderline.

Respiratory infection.
Damp, poorly ventilated housing is the setup. Look for discharge from the nose or eyes, sneezing, and matted fur on the inside of the front paws where the rabbit has wiped its face.

Arthritis.
Older rabbits stiffen in the cold, move less, sit in one place and develop sore hocks and a soiled rear.

Urine scald and a dirty bottom.
A rabbit that cannot reach its rear, or that is sitting in damp bedding, develops scalded skin. In cold weather this is painful and slow to heal.

Encephalitozoon cuniculi and other conditions.
A rabbit with a head tilt, hind limb weakness or incontinence needs assessing on its own merits regardless of season.

The single most useful home distinction is droppings. A rabbit that is merely cold is still producing droppings. A rabbit that has stopped is an emergency now.

Part the coat over the shoulders and rump. A dense dry winter coat sits differently from a damp or thin one.

Setting up for winter properly

Raise the hutch off the ground.
Cold and damp rise from the ground, and a raised hutch is also harder for predators to reach.

Turn the open side away from prevailing wind and rain.
Then add a cover at night that still permits airflow. Purpose-made hutch covers, tarpaulin arranged to leave a ventilation gap, or a sheltered position against a wall.

Bed deeply with straw.
Straw is a better insulator than hay because the stems are hollow. Hay is food; straw is bedding. A deep straw bed inside an enclosed sleeping compartment lets the rabbit burrow in.

Give an enclosed sleeping area.
A box within the hutch, with a small entrance, holds warmth in the way an open hutch cannot.

Provide unlimited hay, and more of it.
Cold weather increases energy requirements. The correct response is more hay, not more pellets.

Use bowls for water and check them twice a day.
Heavy ceramic so they are not tipped, and refilled with lukewarm water.

Keep the run usable.
Rabbits still need to move. A covered section, a dry surface and a cleared area allow exercise without a soaking.

Keep them in pairs.
Bonded rabbits share warmth and cope better. Winter is not a time to separate a pair.

Consider moving them into a shed or outbuilding.
An unheated shed with light and space is often the best of both, provided no vehicle is used in it and it is properly ventilated.

What changes by age, breed and condition

Kits and young rabbits.
Poor thermoregulation and a small body mass. They should not be outdoors through their first winter without careful housing, and a litter needs the doe and the nest undisturbed.

Senior rabbits.
Less body fat, less mobility, arthritis that stiffens in the cold, and a reduced ability to groom and to reach caecotrophs. Many older rabbits are better indoors for the winter, permanently.

Underweight or unwell rabbits.
Any rabbit that is losing weight, has dental disease, or is recovering from illness has a reduced margin and should be brought in.

Rex and short-coated breeds.
Less coat insulation, and rex coats in particular provide less loft. They also have less padding on the hocks, which matters when a rabbit sits still on a cold hard floor.

Giant breeds.
Better surface-area-to-mass ratio for holding heat, but far more prone to sore hocks and to arthritis, both of which worsen with cold and inactivity.

Lop breeds.
More prone to dental and ear problems generally, and a damp cold environment tends to bring both forward.

What never to do

Do not move an indoor rabbit outdoors in autumn or winter.

Do not shuttle a rabbit between a warm house and an outdoor hutch.

Do not house rabbits in a garage where a vehicle is used.

Do not seal a hutch completely to keep the cold out.

Do not rely on a water bottle in freezing weather.

Do not use a hairdryer, an uncovered hot water bottle, a heat pad against the skin or hot water to warm a cold rabbit.

Do not assume a quiet rabbit that has stopped shivering has settled.

Do not reduce hay or replace it with more pellets to add calories.

Do not leave a single rabbit outdoors through winter without seriously reconsidering the housing.

A rabbit that is eating, producing normal droppings and moving about is coping, whatever the thermometer says.

When to get help

Go immediately for a rabbit that is cold and unresponsive, floppy, or has stopped shivering, and begin slow rewarming on the way.

Go the same day for a rabbit that has stopped eating, has produced no droppings or markedly fewer, is hunched and grinding its teeth, is shivering with cold ears and feet, or has laboured or noisy breathing.

Book within a few days for weight loss over consecutive weeks, soiling around the rear, sore or reddened hocks, discharge from the eyes or nose, or reduced hay intake.

Bring the weight record, the dropping history, the temperature inside the sleeping compartment if you have measured it, and what the housing and bedding are. In a winter rabbit case, the housing detail usually explains the illness.