My flock of 11 geese and 7 ducks go through a 50 lb bag of feed per week, I feed them purina flock raiser. They’ll eat more in the winter, about a bag and a half per week at most.
I would suggest looking for a cheaper feed.
Geese can subsist on forage for awhile, but they’re much larger birds than their wild ancestors and so have a higher nutritional demand. When molting, laying, or stressed they also require more nutrition.
How are you feeding your birds also? Is their feed available at all times or do you feed them at specific times?
With mine I feed them once a day, twice a day in winter. The rest of the day they’re expected to forage. Some of my more finicky birds will waste their food if it’s always available whereas other won’t bother foraging if their feed is available 24/7.