Stop feeding bread to ducks.
Bread is junk food for ducks, it fills them up, meaning that they’re less likely to eat foods with nutritional value. Ducks that are fed bread may even become malnourished, and adult ducks eating bread may become fat and overweight.
Also, because of the high-calorie, low-nutrient diet that bread presents, young ducks can develop a condition called Angel Wing which is a wing deformity that usually means that the ducks cannot fly. It’s incurable and it’s all your fault.