The answer is; IT"S A ROYAL PAIN! Fenbendazole given in drinking water won't get the same dose into every bird every day, promoting resistance. Catching every bird for five days running to give an oral dose isn't going to happen here either. There is drug resistance developing some places by some parasites, maybe not everywhere to everything. Having fecals run does help, and worst case, necropsies done also helps. I'm using Ivermectin totally off label here, with good success, also for mites. UGH! I wish there were approved effective choices, and so far there really aren't. I hadn't seen the above bulletin before, either. Mary