Chickens do not have mammalian lungs. Chickens have interior and posterior air sacs. Air enters the trachea, half of the inhaled air enters the posterior air sacs, and the other half passes through the lungs into interior air sacs. These sacs contract during exhalation, air from the interior sacs empties into the trachea and out the chicken's mouth or nostrils (nares). The oxygen in the chicken's lungs is the same as the environment. When being exposed to DE, it is often recommended to use a respirator by OSHA since it is so easily airborne, causing an alarming rate of silica in the lungs. What enters lungs is not expelled, and they don't make respirators for chickens. I would not be surprised if many respiratory problems people experience are from the use of DE since they seem to treat birds and cannot overcome symptoms of respiratory illness. Like I've said before, just because a product is labeled "natural" does not mean it is beneficial.
What do you use/reccomend for external parasites?