Our friend Al at Sweet Meadow Farm in Massachusetts recently started selling a timothy pellet food for guinea pigs. Already known by small animal owners in New England for his organic timothy hay, Al's new pellets smell good (even to us humans), are nutritionally balanced, and easy on the wallet (especially for owners with multiple critters). He also offers food pellet products for rabbits.
Al's products can be purchased online through his Web site. We're also seeing a lot of them at independent pet supply stores (like Pet Super-bowl in Stratford, to name one).