We have 4 ducks that stay in our back yard pond and we feed them once a day; trying to ween them from solely eating duck food and getting some wild fish in their diet. They are doing good with eating fish (we have witnessed them eat some fish); but my question is, when we do feed them, is it normal for them to eat a ridiculous amount? They've always been sort of heavy eaters and I'm just curious because of the whole "eat like a bird" saying.