I have always used DE as I read all the wonderful things its supposed to do. Here recently, I just noticed a few of my birds in the free ranging lock have mites (GROSS!). So for me, it didnt do anything for me and won't be purchasing it anymore. I have read wood ash (like he ashes from burning wood) are great o prevent mites and will be trying that as a preventative. In the mean time, I'm using Sevin dust and if this doesn't work ill be using eprinex (I believe that's what t is called) as it is an ivermectin the product but has not withdrawl periods.