I wouldn’t recommend setting up a pen a rest stops, they would likely be very scared and could escape. Rather, I think you would just want to take a lot of breaks to make sure they eat and drink, because a lot of rabbits won’t eat in a moving car. But, some get used to it and start eating, and eventually will sleep.
I know some members here have made long journeys before, so hopefully they will chime in.
In unfamiliar territory, the carrier is actually the bun’s safe zone, so getting them in and out might be more stressful? I did make a journey of about 5 hours with buns in the car and they did OK. Typically you want the carrier filled with hay, and have some nice fresh veggies to offer as snacks when you take breaks to get some water in them, as they might not drink at all.
Is it possible for you to split the journey into two or three days? I know people have set up pens in pet-friendly hotels when traveling.
It’s also important to think about how easily stressed your rabbits get. Some bunnies will go into stasis over a trip to the vet for a check up, but others are fine with going on adventures. If your bunnies fall in the first category, it would be much better for them to find a sitter who can care for them while you are gone.
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The answers provided in this discussion are for general guideline purposes only. The information is not intended to diagnose or treat your pet. Seek the advice of your veterinarian or a qualified behaviorist.