I thought I'd post this here, because I had a hard time finding the info about deworming waterfowl myself. I emailed one of the waterfowl farms where I've purchased some of my birds. My email: I have questions about deworming waterfowl and I seem to get a lot of mixed information when I Google it. How and with what do you deworm your ducks and geese? I've had waterfowl for years and have never dewormed them, but their feather quality this year has been looking a little rough and I've noticed some diarrhea, so I thought I'd deworm them. Response: We do not routinely deworm our waterfowl, but if necessary, we recommend using an oral dose of 1% injectable Ivermectin for Cattle & Swine (NOT Ivermectin + clorsulon) at the following rate: 1/10 cc per 4 pounds of bird.