Thank you so much for taking the time to respond, Redbrew! If my bird were based strictly indoors, I'm sure every 3 weeks of Ivermectin drops would be sufficient. Tricky situation that he enjoys spending time with the outdoor flocks, but I know he would be unhappy if I forced him to stay indoors. Would you happen to know how long the mite-killing effects of Ivermectin last in the system of our birds once applied behind the neck? Does it wear off after only a few days? I initially thought it would kill any new mites that bit him up until his next dose, but considering they say repearğtreatment after 7-10 days is necessary to kill newly hatched eggs, I suppose it does not stay effective for any longer than that?