If you really want to research the research, visit your County Extension agent. They are constantly asked questions about DE, so they are used to pointing people where to go. Or, got to ATTRA (
http://www.attra.org/ ) which had 48 articles when I searched the term Diatomaceous Earth.
I happen to have a hard copy of this one in my office and found the electronic version through Google.
http://129.186.41.143/research/gran...ve_Parasite_Control_for_Sheep_[_Organic_].pdf
This trial was ran by Iowa State University, so I guess you can say the public paid for it. If you think well "sheep are sheep, we're talking chickens" then I also found articles for cows, goats and pigs... so I'm sure you can find some chicken specific trials if you just google for awhile.
Like I said above, I reallywish DE worked.
But, there are thousands of variables as to why someone could claim sucess with DE. The largest, of course, is weather! If you live somewhere with cold winters and hot summers, you've probably never had to deworm more than twice a year, and Coccidiossis is unheard of. Here in wet coastal Washington, it rarely freezes and never gets hot in the Summer. The parasite cycle is year round and I deworm at least 6 times per year on my goats and sheep. But, I do fecals at least twice a year to be sure I'm not going overboard with it. So, with such variables, how can anyone really say it works? Maybe they just have clean pastures to begin with?