My yard is 1/3 of an acre. When it rains heavily, it floods terribly. Thankfully it is not often since I'm in Southern California. We are supposed to get heavy rains this weekend. My coop is on a high side of the yard but may still flood 2-6" in water. The water comes in from the neighbors yard. Question is, will my chickens drown if they decide to go down to the bottom of the coop? 2nd question is, I bought a bag of DE and it says for pets. Is this what I can use in the coop and or in a dust bath or will this hurt them? Do I need "FOOD GRADE DE"? It says nothing on the bag about being food grade so I am nervous to use it. Thanks a million!