I free choice in 5 gallon buckets suspended in the air (hanging from a chain). The only time I had a mouse problem was when I inadvertently put a branch close enough for the mice to climb into the feeder! I moved the feed away from the branch and the issues stopped.
This article says a good estimate is roughly 1/2 cup feed per bird per day though. So, if I had to measure for my flock of 13, I'd be feeding about 6 1/2 cups each day. I don't know about the geese and ducks, but if your signature bar is current, that would be 10 cups of feed each day, plus whatever the goose and ducks need.