Two clerks at TSC had no idea what I was talking about when I asked about food grade diatomaceous earth. About two weeks later, I was in a Farm and Fleet and saw food grade diatomaceous earth powder. It looked like very finely ground brown dirt. Not being sure about the "powder" part, I left it. Would the powder have worked for the chickens or do I need to keep searching for just food grade diatomaceous earth? Since diatoms tend to be white, I guess I was expecting a very light colored, even white, substance, like what is used in diatom filters for aquariums.