I've been reading about DE in the chicken runs and how safe it is. So I bought some at Tractor store. I picked up garden safe DE, it says it safe for pets, indoors, even your bed but nothing on chickens. So I went on the website and it said do not use on chickens and it is not food grade. I kept reading and all got out of this is that it is natural DE and might have some impurities in it. My question is has any on used this on their chicken run.