I've been using a mix of aspen and equine fresh with my asf rats. Only in the grow-out/feeder tubs where there are higher numbers of rats. The stuff is awesome for sure but I still need to work on how much I'm using since it doesn't last nearly as long as a bale of aspen does. I love the clean up though with EF, in the pee area in the tub there is no bedding material sticking to the tub it poors right out. Its kinda like one of those eye openers when going from glass aquariums to tubs LOL. I wish I could buy a larger bulk for a lower price though.