We had a duck that laid 14 eggs over a period of three weeks and then sat on them for the duration hatching 11 of them successfully. That was in my back garden in UK - a wild bird.
At our smallholding our goose laid just five eggs in a clutch and then sat. Prior to that the eggs she laid were left in her nest for her, but she didn't sit, and eventually the eggs were either broken by the other geese or the pig got to them.
She only sat when her instinct told her to. She actually didn't hatch out a single one - I had to buy goslings from the market, put them under her at night and the next day she was happy with her new family and handed her young over to hubby who carried on raising them!
She will know when the time is right to sit, or may not sit on a nest at all. With the chickens, some sit some don't but most all of them lay. Maybe it is a personal thing!
Kate