I had a rice box a while ago.  Out of 6 ferrets, 1 of them ate the rice.
The rice in her poop had not expanded, as long as you use regular
non-instant rice.  However, her poop was FULL of rice.  I was worried
that she wasn't eating enough "real" food.  Someone also thought it was a
litter box.  So, we got rid of the rice box.
 
Last night I was at the Stop N' Shop and saw that all of their Easter
stuff was 75% off, including the plastic easter eggs.  For $10 I bought
enough plastic easter eggs to fill a 2 ft x 1.2 ft x 1.2 ft box.  The
eggs are too big to eat, and I remember someone using ping-pong balls.
We'll see how they like it today.
[Posted in FML issue 3756]