How do I tell if the eggs are fertile?

It is virtually impossible to tell if an egg is fertile prior to incubation. Once incubation has begun, eggs can be tested by candelling. This involves shining a bright light into the blunt end of the egg. If the eggs are fertile, small red veins will be visible after a week or so. By 8 days, there is a network similar to a spider web. If this is not visible, the egg is infertile and should be discarded. An infertile egg can go rotten and jeopardise an entire batch.

The fresher the eggs the better. Eggs after the first week start to deteriorate. If you can set eggs weekly that is best, if eggs are older than 14 days the results will often be very disappointing. In a nest the duck or hen turns the eggs and they store better, so with mum's help nest eggs often hatch after 3 weeks.