I use aspen for my boys too, but all they smell like is food and Bar BQ, hehe. 6 boys in 1 cage, 4 in another, 2 in another, and one by himself. They all eat Mazuri too, the 9F. I dunno! Maybe you're just more sensitive to the smell than I am(I've done necropsies on dead dogs who have been in someone's trunk for 2 days in Texas summer, so I'm not bothered by alot, LMAO).