To stay healthy, it is vitally in-paw-tent to eat hay... Lots of hay... As much hay as you can in fact.

We keep trying to encourage the 2-foots to eat it by spreading it around the place, but being so inherently stupid they always fail to take the hint, in fact they spent an inordinate amount of time gathering it up and throwing it away!
Still... As they are both old and knackered they will probably die soon anyway, put even so, I feel duty bound as a responsible pet owner to try to help them.