Help I have a flock of around 200. They continue getting sick. There ages five from 2yrs old thru 1wk old. Meds I've tried tylan and doxy. There water is cleaned twice a day and they eat the best food there on purian. They also get treats. They have running noise, wheezing and sneezing. For the most part I do everything natural. There clean of mites. We've be fighting this for on & off for 3mts.