<p>
</p>
<p>I am pretty sure it is the piggy itself… we used Carefresh bedding, which is made from wood pulp. I absolutely love them – I always stop and chat for a moment with the piggies on display when I go to the pet store for dog food. I happened to be at the Arizona State Fair when visiting the state several years ago, and one of their exhibit buildings had hundreds of guinea pigs on display! I admit, I went around and talked to every one of them. Quietly, of course. :)</p>