Answers: Not all eggs are fertile. You don't need to verbs, as eggs you eat might be furtile, there is nothing living inside that egg, unless it have been sat or, in an incubator. Then, after going on for 24 hours, the duckling starts to form. As for the sitting, some ducks may never sit in their lives, as with ducks, chickens and so forth, the do not sit to lay, like frantic birds, or birds in an aviary, they lay to sit. If they choose to sit, it will normally be when they have a clutch of roughly 10 eggs. So do not worry, your duck is fine, you do not need an incubator, as there is zilch to kill, the duckling hasn't formed. You duck will sit when she is ready, and only after.