Some, myself included, use garden lime as an odor eliminator in the coop. It is cheaper than anything else, among other things. But I just read this on the bag of pulverized dolomitic limestone that I use in the coop: contains a certain %age of 'crystalline silica', prolonged occupational exposure to, or breathing of which, can result in lung disease and/or cancer. I am NOT using the burning masonry lime, just 'sweet' garden lime. But reading this makes me do a double take. Maybe we shouldn't use this stuff for our birds to scratch in and breathe--even tho we sprinkle just a little for odor control. Thoughts??