I use pine pellets for adult rats. Birthing mothers get aspen shavings. When the babies are two weeks old they get switched to a combination of sani-chips all over and aspen shavings for the nest. Sani-chips only for the grow out tubs.
ASF's get pine pellets in the corners and sani-chips & aspen shavings. Mice do not get pellets, just sani-chips and aspen shavings.
Rats and ASF's give off no odor for up to two weeks. They go in the same corner so you can spot clean. Mice just stink.
When I use up my aspen shavings I am switching to pine shavings. The pine really helps with the smell.