I’ve noticed that the Aspen shavings don’t work as well as the Aspen pellets, but I LOVE those and actually use both. The Aspen Supreme pellets are a wee bit more expensive, but they last much longer and soak up the whole odor. What I do is put a layer of those in her litter pan, then a light cover of Aspen shavings to keep it soft and freshen it up. The pee soaks down into the pellets which expand to absorb it.
Feline Pine (unscented) works the same way but the Aspen kills the odor a bit better and is a safer wood. But FP is cheaper, so you could try those. Also that co. makes Equine Pine – they’re all the same as long at they are unscented. It’s the Wood stove pellets that contain an excellerant that are the dangerous ones. I’m sure Yesterdays News, for rabbits or cats, would work too.
Just be sure to avoid Pine Shavings of any brand. Those are hazardous. If you bunny will accept pellets without shavings and be happy with pellets alone, then Aspen Supreme, Feline Pine or YN are the best I think.