I thought that ducks would sit on those eggs that were fertilised so we would know they were fertilised and therefore leave them there. Our ducks aren't sitting on their eggs (even though we have witnessed many mating incidents). Someone told us that we should let the eggs accumulate and then the duck would sit on them. Is this correct?
That might happen. In my Runner flock, I have found some go broody, some don't. With my broodier girls, just the sight of a pile of eggs makes them get all cooey and start talking to the eggs. But with some, they seem to have no interest at all.