When a hen duck lays her egg and leaves her nest for a day will she come back?

Answer 1

When people are around, ducks will spend little time on their nest. The duck is more concerned about not having intruders find the eggs, so she is very active to draw their attention away from the nest. However, she usually settles down at night and protects them from the cooler temperatures.

I have found that if the duck has been broody for two weeks, and her eggs are infertile, she will abandon the nest, take a break and start again later. The infertile egg does not maintain it's temperature, and even when under the duck all night, it stays cooler than a fertile egg which is generating heat on its own. If it is only one or two "dud" eggs, then the duck will not sit on them, but will push them into the nesting material. That way, if they should become rotten and explode, they will not dirty the good eggs.