Rabbits - burrowing animals, which means they live in burrows, which pull themselves. Dig it pretty deep. Up to half a meter in depth there. You can cook a rabbit tunnel of cardboard, plugged at one end with cotton or hay. Rabbit will gnaw, and there, and dig. You can also purchase a special cloth on the frame tunnel - the rabbit will run through it here and there, and if one end of the wall up the old towel, it will be more interesting.