Each bunny is different when it comes to traveling - some are seemingly stress-free while others scamper away at the sight of a carrier. I hope these tips will make you and your bunny's travels easier.
Some bunnies prefer to ride in smaller areas, such a plastic dog carrier, to feel hidden. Others like to take advantage of a roomier small cage with a tiny litter box. I don't recommend cloth carriers as small pets can chew through them and the carriers leak when it comes to urine or water. For flooring, towels or blankets must be folded thickly as they tend to bunch up as bunnies attempt to burrow, or a thin towel will often slide right along with the bunny on a sharp turn. Using a stiff rug (particularly one with a rubber backing for traction) or a pet bed that holds its shape well works much better. The pet beds are generally more absorbent when it comes to liquids as well, meaning a more comfy ride for bunny. On longer rides, some of our volunteers have had great success with adding a small plastic tote (meant for shoes, usually found at the dollar store for $1-2) as a litterbox for small-medium rabbits as it fits in most large-XL pet carriers.
You'll want to get your bunny used to the pet carrier before the trip so it's a familiar and comfortable place. Place the carrier with the door propped open in your rabbit's area so the bunny can get familiar with it on their own terms. You can also toss a few treats or veggies inside so they'll investigate at their own pace. Hopefully they will begin to use it as a cozy spot to snuggle and come to identify it as a safe haven when the times comes for a trip. Once familiar, try short trips around the block or around town to see how things go. These trial runs are a much easier time to check up on your bunny's reactions to the trip, and to stop and rearrange things if needed.
For water, I personally dislike water bottles on the carrier door during the trip as they vibrate and leak almost incessantly. I have found one water bottle that is virtually leak-proof yet still offers a decent amount of water when pressed on. You can find them on Amazon here - Choco Nose Water Bottle. During a long trip I offer veggies with a high water content (and often soak them in water the night before) such as celery, bell pepper, and lettuce to keep their hydration levels up if they are too uneasy to drink. Be cautious if you don't give veggies regularly. I would bring a bottle and a bowl (as rabbits can drink more from a bowl) and offer it at all stops along the way and overnight. Some will drink right away while others take a minute to get curious once the vehicle has stopped and the vibration of the motor & roadway has subsided. The veggies will also give them something besides the hay to nibble on as they ride as nervous ones may be more inclined to eat flavorful veggies over their regular hay.
When it comes to packing, create a travel bag for your bunny to keep in the vehicle in addition to all of the things you will use overnight or at your destination. Bring along a water bottle with water from home, a bowl, extra veggies, a little hay & food, and additional beds/flooring and litter in case it gets wet or is well-used throughout the trip. Pack it where you can get to it easily, that way you don't have to unpack an entire box to get to more hay or supplies. It is also a good idea to pack a larger container of water that you normally give (whether it's local tap water or bottled water) along with your regular supplies, as sometimes the new water tastes differently and they are less inclined to drink the water from the tap at your new place. Having water from home will prevent GI stasis if they don't want to drink, and after they are more settled you can start mixing in the new water. Your bunny may be too stressed to eat or drink right away, so another great way to be prepared is to have Critical Care and syringes on hand. Dr. Leslie Pence of Avian & Exotic Animal Hospital of Louisiana says "The issues I usually see are GI stasis related to stress or diet change, etc. I would recommend every person traveling to ask their vet for a bag of Critical Care and start it if your rabbit doesn't eat or poop for more than 12 hours, and to also start if the poop changes shape or texture, as this may be a sign GI issues are just starting."
The size of the carrier and vehicle will determine the best placement. Usually I recommend that they ride in the backseat where air circulation is good, but not with an air-conditioner vent blowing right at them on full blast. If you use a regular cage, you may want to have a make-shift sun shade, whether on the window or over the top of the cage. You'll also want to make sure it's as level as possible. This can be done by rolling up a spare towel (or even dirty clothes that you don't have time to wash!) and put them under the cage to balance it out up against the back of the seat. Positioning the carrier sideways vs front to back will help in 3 ways - a long cage or crate won't tilt when the bunny hops from one side to another, it allows you to buckle the carrier in, and if you were to brake suddenly or get rear-ended, the bunny won't have as far to go from front to back which will lessen the potential for injury.
The trip itself will likely be easier than all of the packing & prep work. Plan to stop every 2-4 hours to give your bunny a 5-15 min break and give the opportunity to drink some water. Keep an eye out for any drooling (indicative of nausea) or panting (possible overheating).
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