predators

With spring just around the corner i am looking into several fly control systems and ran across fly predators and was wondering if any of yall have used them and if they are worth the money and if the control all flys like the midge fly that carries ehd or if it only takes care of certain types...

I'm am seriously considering using the fly predators this summer. Wondering if there are any deer farms that use them and the success you have had. When you go into the order information...they don't have deer as a livestock option. So if you are using them, do you use "other small" or "other...