Is an egg from a duck fertilized upon laying if male is present and has mated with the female or does fertilization occur after laying?

Fertilization in ducks occurs internally, before the egg is laid. When a male duck mates with a female duck, he transfers sperm into her reproductive tract. This sperm can fertilize the eggs as they are released from the ovary and travel down the oviduct. The egg is then covered with layers of albumen (egg white) and shell before being laid. Therefore, if a male duck is present and has mated with the female, the eggs she lays will be fertilized upon laying.