1. Don’t feed wild animals. For this rule, the particular type of food doesn’t matter. Wild animals are harmed from human feeding, even if the food is nutritionally beneficial to them.
2. Bread spoils fast, and spoiled foods in the environment can make a lot of animals sick.
3. Bread doesn’t contain the nutrients that many birds need, so birds (especially young birds) that eat too much bread at the expense of not eating other foods might become unhealthy from deficiencies on other fronts.

I point out these three distinct reasons because the overall points being made don’t make it OK to feed wild ducks peas or whatever else. For farmed animals, though, farmers will want the overall nutritional profile to meet some standard, at which point old bread and other scraps could very well be part of a broader diet, in a way that manages household waste.

You misunderstand, riding trains increases the amount of shitposting capacity one has.