I just saw something on TV about feeding ducks, geese & swans bread. It seems its not so good for the them. Some are getting overweight. They said better for those birdies to diet on oats and other grains. I believe they said feeding them gluten free bread is better. Looking in to it seems a few wildlife folks are urging the public to switch the feeding to a more healthy diet. Most of what I read online about this is posted in the UK. I guess these waterfowl are like me and pizza when someone puts one of those in front of me, I dang near will eat every slice and care little of stopping.