I am a newbie looking for advice. I know you are not supposed to raise chickens and turkeys near each other but I am going to attempt it. There has not been any poultry on my farm for many years. My wife does have horses. From what I have been reading on here is that "Black Head" is what I need to be careful of. I have been reading the Food Chemical Codex Grade DE is the way to go. It is hard to find. I stopped at a local pool store and they had Celaton Diatomite EP minerals.ISO 9002 Certified. Is this the same as "Food Grade"? I have searched and can't get a difinative answer. I do have my local Farmers CO-OP looking for it as well. Any help would be appreciated.