I was at Tractor Supply yesterday, and I was talking with a lady there who recommended DE to keep mites, and other pests away from my chicks. She said to sprinkle it in their coop, and run and any dust bathing areas? I bought the Red Earth brand. Is it safe? It doesnt say it's food grade....what can you use instead of DE? My chicks are 4 1/2 weeks old and go out just during the day when it's warm.