mipsy6 you might want to google these companies: "Woodstream" is the parent company, then "Saferbrand" is under them and they distribute the "Concern", Could find no product safety data on their DE and it seems the parent company's primary products deal with the eradication of moles, mice and rats. Sooooo, I dont know what to tell you. If what you found is true about the crystalline silica being so low, in of by itself it may have started out as food grade but with EPA thing going on, there may be insecticides in it and it might be harmful to your chickens. Hope this helps in some way!