RURU one time I asked a fellow who worked at our only feed store[and he had chickens] what kind of wormer to get, he told me to use bleach in their drinking water. Well I just about feel over, kinda goes with how people use to worm their dogs down south here, chewing tobacco is what they gave them.People who have geese seem to learn by experience on what to do or not do. Not all the people you ask know everything about geese at a feed store or old farmer's ways. Remember the BEST feed for geese is waterfowl or gamebird feed. It has the proper amount of all the vitamins they need. But if one likes you can also use brewers yeast for animals not the kind that rises bread that is a no no! But you put I believe one cup per 10 pounds. It has niacin and vitamin B in it..