After we found out that our Red Star hens/pullets and RIR rooster have roundworms, we immediately started looking up info. The two brands that were recommended for us to use was Wazine and DE. So, we decided to get DE. Well, we still haven't gotten it because first I had to talk my dad into buying it because he was hesitant at first, since it was a 50 lb. bag. I told him that it can also be used on plants as a natural pesticide, and it can be used in coops and stalls. Plus it's a natural dewormer. So, finally he went to get it. He called me back to ask how much to give to them. But first, I asked if he made sure that it said, "FOOD-GRADE" on it, and not "POOL-GRADE", because I read here from someone that the pool stuff has silica in it, which is poisonous. He said that it was for pools. So I toldhim NOT to give it to the chickens! He brought it back and told them that he needed FOOD-GRADE DE, bot the pool stuff. But then they said that you have to order it and then you go and pick it up(It's at our local paris farmer's union and they do the same thing with chicks...you place an order and wait for the chicks to arrive). So now we have to wait again! But anyway, once we get the right DE, how much to we add to their food??? And how often or for what period of time do we add it??? Thanks!