Pine is readily available, cheap and smells fresh. This is OK for your rodents. I use pine as a substrate for my rats, mice, etc. Actually some people report mice get allergies from pine, mine have not. Theres many top breeders that use Pine also, Ralph Davis to name the best :gj:. Anyways Aspen would be great, I just dont use it because nobody local carries it, as I said, Pines worked for me for years.......and many top breeders too. DO NOT however use pine or cedar as a snake bedding, Both are extremely harmful to snakes.