I use peat moss under my roost to keep N from gassing. From my trials I believe it to be successfull. I also do the deep litter method during the colder months to provide heat.

Hmm, I did not know that! But I've never had chickens either.

I would think any kind of high-carbon material used for bedding would help absorb the nitrogen. Sawdust or wood chips comes to mind, and you can get it in a compressed bale sold as livestock bedding.