I use it in and around my coop and run and it definitley helps with and odors and dampness. I put a little bit it in their yogurt every once and a while as a wormer. When my mini donkeys got lice I started using it in the coops and dusting them off from time to time as a preventative. Google it, theres tons of info on it.
You have to make sure its "food grade" though, the Codex brand will be white and it will say it right on the bag. Red Lake Earth makes it too but they add some volcanic ash to it which makes the color ashy. Its the same stuff though, the Red Lake Earth is much cheaper. I found it at my local Agway. Im sure you can buy it online.