I would have told her off:
5 reasons why bread is bad
- Ducks need a varied diet to be healthy. Bread doesn't have much nutritional value and fills the duck's stomach so that it doesn't forage for foods it would naturally eat, which can lead to malnutrition.
- Uneaten soggy bread can cause a build-up of bad nutrients, which can lead to more algae growing around water, more diseases and more pests, such as rats.
- Throwing bread into a canal or river can create an unnatural overcrowding of bird populations, as the birds will flock to the same location in search of their starchy treat.
- Too many ducks or waterfowl in one place can stress the birds and lead to their habitats being damaged.
- This also creates excessive amounts of bird droppings, which, along with being smelly and slippery underfoot, can reduce water quality and clog waterways with harmful algae.
https://canalrivertrust.org.uk/enjoy...20malnutrition.