We use PetsPick KILN DRIED Pine from WalMart. The kiln drying removes the phenols from pine making it safe for small animals, while cedar in any form is toxic and why it is used to line hope chest and doesn't smell as bad a moth balls. Been using Pine for more than ten years and have had several of ours go past the ten year mark. Coal passed away in May at 13 1/2 and she'd been around pine bedding her whole life.