While you might not want to leave your bun out for prolonged periods in very low temperatures, rabbits can usually withstand temperatures as low as 15° Fahrenheit.
Watch Your Bun Get More Active in the Winter
Both indoor and outdoor pet rabbits are energized by the cold. It makes them playful -- jumping, hopping, doing zoomies, and turning binkies (joyful, leaping twists happy bunnies sometimes do). Their environment should allow for them to fully exercise year-round, no matter where you decide to locate them.
All that energy and the colder weather means that your bunny now has a larger appetite. Making sure that they have a steady supply of fresh and clean Timothy Hay or Orchard Grass will keep your small pet happy and healthy in summer or winter. Adjust their food portions with the seasons and add extra hay in the colder months of the year.
If your bunny uses a water bottle, in the winter, switch to a low-rimmed bowl it can reach. Your rabbit can still lick the frozen surface.
From Sploot to Loaf
In hot climates and seasons, rabbits will “sploot,” i.e., lie completely flat on a cool surface to lower their internal temperatures. Conversely, when it turns cold, observe your bun. It becomes a “loaf” of rabbit. It huddles itself close together to conserve heat and stay warm. These are examples of normal and basic bunny behavior.
Home Is Where Their Hutch Is
Pet rabbits need more than a cage set-up in the winter; they need a hutch. When you build a rabbit hutch (or situate a pre-made model), you can reduce the impact of cold drafts and headwinds by facing the hutch southward toward trees or shrubbery. If there’s no natural barrier, place it strategically on a porch or use a shed or garage wall for a windbreak. All hutches should be built off the ground to reduce the cold, and for protection from predators.
Winterizing Their Hutch Is Key
While rabbits can withstand cold temperatures, they are particularly vulnerable to getting wet. The hutch should be protected year-round from inclement weather, but in winter, this is even more vital. A wet bunny can quickly die of hypothermia.
Hypothermia can be avoided by tarping their hutch securely. Routinely check for any rips in the tarp or leaky spots that could let water into the hutch. Whatever you use for bedding, you will need to add more of it when winterizing the rabbit hutch. In the wild, rabbits burrow underground in the winter to stay warm. You can simulate those conditions by ensuring they have plenty of bedding to burrow underneath.
Adding Insulation to the Hutch
Depending on how cold your winters get, you have a couple of insulation options. Placing blanket-covered cardboard along the walls of the hutch is usually sufficient unless you live in a much colder region. There, you might want to add thick wood panels that can be removed once the weather warms up in the spring.
For the floor of the rabbit hutch, cardboard or newspaper that you change regularly makes a good first layer. On top of the first layer, scatter lots of fresh grass hay. Just as we humans do when we spend a lot of time outdoors in the cold, rabbits also need to consume more calories during the cold winter months. To keep it always on hand, you can order farm fresh hay shipped straight to your door from RabbitHoleHay.com. Not only does hay serve as a protective layer of warmth, but it they can also munch on it as extra food along side their normal, daily pile of hay.
When It Gets Really Cold, Transition
Those living in some of the northwestern states, New England, and the areas around the Great Lakes can experience temperatures so low that they are incompatible with life for outdoor pet rabbits. But bringing a bun that has been living outside in the cold into a warm house can cause such a shock to the rabbit’s system that it can’t recover.
The best way to accomplish this is to gradually transition your rabbit to a warmer environment. Construct a temporary hutch in a shed, garage, or outbuilding. Put a heating unit in there that is completely bunny proofed. Don’t turn it up too high. The idea is to reduce the shock to the rabbit’s system and gradually warm them up.
No place outdoors for a warmer hutch? An enclosed porch with a blanket added as draping over the top is an alternative. If your only option is to bring your bun indoors, choose a room that is already naturally cool. A fruit cellar in the basement would be ideal. Even though it seems way too cold for you, for a rabbit used to outdoor temperatures in winter, it's a cozy alternative to a freezing hutch.
If you don’t have a cold basement, shut the heating vents in the room where you relocate your rabbit. If it still feels too warm, crack a window. Keep that door closed and your bun inside it. But remember to spend lots of time interacting with it and making sure it’s transitioning well to an indoor environment.
If you decide to keep your pet rabbit outside during the winter, just remember to make sure it has a properly winterized hutch, added insulation and bedding, and remember there is a point where it can become too cold, and you will need to transition your pet rabbit from the cold outdoors to the cozy indoors.