A lot of people do not worm ducks. Internal parasites are not as common in ducks as in other types of poultry. We occasionally worm and have used various things. A lot of people on BYC seem to use Ivermectin, but I don't think it is a very comprehensive wormer for poultry (certainly not for internal parasites anyway). The most comprehensive poultry wormer is Flubendazole, but it is very hard to find in the US. The last time I tried to order it, I only found one dealer in the US even selling it (you might google it though). You can also use Fenbendazole. Safeguard is probably the most readily available form, but if you have a large number of birds, it is kind of hard to dose (the crumbles, maybe the liquid is easier). Anyway, there are various other less comprehensive wormers that will work on ducks as well, like Piperazine. These are some of the more frequently mentioned ones, but you might be able to find others online or through some of the poultry or vet supply places.
