Tartar Control cat treats make excellent ferret treats. They DO help immensely with keeping teeth clean (but you should STILL brush your ferret's teeth regularly). Most of them contain corn gluten meal to which some ferrets are sensitive (allergic), but unless they eat more than 5 or so at a time the amount is negligible. I took a sheet, cut it larger than the top of the play pen, hemmed the edges, and ran a draw string through the hem so that it could be tighten around the play pen. It's not enough to keep in the most determined of the most determined but it will work for most. Debi Christy Ferrets First Foster Home Practical & easy training, care, & maintenance articles available at http://www.geocities.com/ferretsfirst/ [Posted in FML issue 3790]