Please don’t kill us with bread!
Bread is actually a danger to ducks and other waterfowl. It causes Angel Wing, which causes feathers to grow too quickly. This strains muscles and can prevent birds from flying.
Bread causes fatal heart and gut disease in swans.
Bread is bad for the water environment – it rots, and pollutes the water. This encourages bacteria to grow and encourages rats. It causes algal bloom, which gets into birds’ lungs and kills them.
If you want to feed waterfowl, lettuce, peas, and sweetcorn are great choices!
For more information, here’s a good article in Popular Science.