The first opinion is right if you use the fgDE cautiously and follow instructions. It surely helps but perhaps it’s not as good as claimed.For years I was always under the impression that Food Grade Diatomaceous Earth was good for all kinds of pets and even humans to eat. I've also read many articles on using it for your chickens to dust bathe in etc. Now with that said, I had just came across another article that says quite the opposite. The article I read said absolutely do not use Food Grade DE on chickens, that it is toxic to them and that it is also a carcinogen to pets and people!!!! What the heck are you supposed to believe???
The food grade DE is not toxic. It helps against things the pharma sells expensive medicines and poisons too. So obviously there is a risk the commercial pharma writes articles to undermine a cheaper non toxic alternative.
I use fgDE for 8 years now. Started with it as red mite prevention. It seems to help for other parasites too. It never caused problems. My oldest chickens are really healthy senior chickens. Not only because of the fgDE. I believe the non-toxic organic feed and the free ranges hours contribute to that too.