bed for bunny that they can't chew!!

I want to get my arthritic bunny a bed to make her more comfortable. I have tried a cat bed and vet bed in the past which were both chewed! the bunnies are not particular chewers but seemed to chew these! any advice on types of bed that seem more durable but still comfy and snug? they do have a plastic bed which i fill with hay but they aren't using it much. They also have carpet which they haven't chewed but wanted something with a bit more padding and comfort.

My rabbits only have beds made from hay or straw. Sure they eat these too, but its better than buying another cat bed every week:roll: