Rabbits in general tend to dig, even when they're fixed. It's a natural behavior -- in the wild they'd dig a burrow. It's much like a cat sharpening their claws. Some rabbits really enjoy digging, and we've built dig-boxes for them before. Some just dig a little, here and there.
We are as gods to the beasts of the fields. We order the time o' their birth and the time o' their death. Between times, we ha' a duty. - Terry Pratchett.
"Men have forgotten this truth", said the fox, "But you must not forget it. You become responsible, forever, for what you have tamed. - Antoine de Saint-Exupéry