Feeding in a Pond
Our goldfish thrive and breed in our pond without us feeding them. Nature provides the food from the trees, plants, insects etc. around.
Why do your readers' pond goldfish need feeding?
Your situation would be the exception.
Most readers' ponds have a much higher fish density compared to a natural waterway that would support a Goldfish population.
To sustain a population of Goldfish, a pond must have a very low fish density, and be able to provide 1-2% of the fish population's body weight in food daily all year round, except during winter.
To enable this to happen, the pond would need to have flourishing aquatic plants suitable for Goldfish to eat such as Elodea Crispa or Elodea Canadensis (oxygen weed), not something like lilies or Vallisneria.
The pond would need to be close to ground level so worms and other crawling insect life could fall into it.
There would need to be an area where the Goldfish can't reach that provided a safe area for flying insects to lay their eggs, and so the larvae would be another seasonal source of food.
You mention that your fish also spawn in your pond. For that to occur, Goldfish need to be well fed and healthy.
The downside of this is nature takes up any excess capacity a pond may have by increasing the fish numbers.
If the numbers are allowed to increase to the point where all available food is eaten, during early spring when Goldfish are coming out of hibernation, there is often a die-off of fish that didn't get enough food in the autumn.
Autumn feeding should provide enough fat to carry them through winter, and allow them to get into breeding condition in early spring. If they can't do this, it is nature's way of regulating the fish population.
Maintain a careful watch on the health of your fish and fish numbers. If they start to look under-weight or you notice a number of deaths, you may need to start feeding them or reduce numbers.