Natural behaviour for rabbits in the wild is to burrow.
By providing your rabbit with a Digging Box it promotes healthy enrichment.
Rabbits will have great pleasure in digging and shredding. You can use soil however this is messy. You may want to use child safe play sand or shredded paper.
Be sure to supervise your bunny whilst using the digging box as you do not want them to start using it as a toilet, avoid using materials such as hay and straw to discourage this behaviour.