Will Ducks Sit on Unfertilized Eggs?

When we had backyard ducks, it was always sad to watch them go broody on a pile of unfertilized eggs.

Female ducks do not need a drake to lay an egg and will begin laying at the 16th-20th week of age.

Occasionally, a hen will sit on an egg so long it rots and explodes in the nest, contaminating the entire nest.

To find out more about ducks laying eggs, keep reading! 

Duck Nesting Behavior

Ducks will use nesting boxes like those sold here and reusable nesting pads sold here on Amazon, but they will often sneak off and build nests in odd, hard-to-reach places.

We had a stubborn duck build a nest between a cinderblock wall and a wooden fence, which was quite troublesome.

Mother nature knows best, so we left her nest alone and let the duck do what the duck did best since we wanted her to hatch eggs.

The hen will dig a hollow out of the dirt and rocks and line the nest with materials she finds nearby, such as twigs, leaves, and grasses.

The more concealment the nest has, the better to foil potential predators as far as the hen is concerned, and she will pull vegetation over the nest and herself.

After incubation, the hen will pluck her feathers from her breast for nest lining and cover her eggs.

The plucked downy feathers will provide insulation, and her warm “brood patch,” or plucked area, on her belly will warm the eggs better.

Ducks turn the eggs with their beaks to provide even warming and development, which is why some commercial incubators have automatic turners.

If you want to check if eggs are progressing or if she is sitting on any dead duck eggs, “candling” them by shining a bright light through them in a darkened room will allow you to see the egg’s development.  

The Normal Hatching Process For Ducks

The average hatching period ranges from 18 to 30 days, depending on the duck breed.

A duck will lay an egg once every 24 hours, it being fertilized during formation in her oviduct.

Further Reading: How often do ducks lay eggs?

The egg travels down the reproductive tract, encounters the drake’s sperm, and is fertilized.

Depending on the breed, ducks can store sperm for over two weeks in their tubules, so even if the drake is gone, a duck may lay a fertile egg for a few weeks afterward.

A nesting duck does not know if an egg is fertile or not until the egg either hatches or doesn’t hatch on time.

After the incubation period and a final “lockdown,” where the hen does not leave the nest, ducklings will hatch.

Average incubation days are about 28 days, but a Muscovy duck, for example, takes about 37 days to hatch.

Because of this difference in incubation times, it is important to let a duck have access to her nest for at least 47 days.

A duck hen’s clutch can range from 1 to 13 eggs per clutch, although I have seen ducks attempt to sit on more.

The more well-fed a duck is, the larger clutch it will have. 

A skinnier duck will not have the resources to devote to laying a large clutch.

A hen will lay eggs for up to ten days to make a clutch, not sitting on the nest, merely laying them, then going about her normal life for extended periods.

Once the hen has laid all the eggs she is going to for her clutch, she will start the egg incubation period of sitting on the nest and incubating them at about 99.5° degrees Fahrenheit (38° C).

Because duck incubation begins for all the eggs simultaneously, all the eggs will hatch at around the same time. 

Further Reading: Is OK to move duck nests if it has eggs?

How to Break Your Duck’s Broodiness

A broody duck will not lay new eggs and only leave the nest three or fewer times a day for brief periods, so sometimes it is better to break her from being broody if she does not hatch ducklings.

Empty the nest box if she uses one, and ensure the duck house is not an attractive nesting spot.

If she has made her own nest, find it and remove the unfertilized duck eggs.

Removing the eggs should break the impulse to sit on them, but it may take a few times.

If the hen returns to the nesting spot, even though you have removed the eggs, remove the nest and all nesting materials in the immediate vicinity, if possible.

If removing the eggs and nest do not work, put the duck in a safe, sheltered cage with food and water for a few days so she will forget all about nesting.

Using a frozen water bottle or ice chips under the broody duck can help break the broodiness by reducing her body temperature.

How Do You Know If a Duck Egg Has Been Fertilized?

Pick an egg and crack it into a bowl. 

Look for the “germ spot” or the germinal spot.

The germ spot is a white spot on the egg yolk, looking quite a bit like a bullseye.

A non-fertilized egg’s germ spot will be blotchy and solid.

Another less wasteful way to see if the egg is fertilized is to candle the eggs and check for the development of a duckling.

Veins develop by the 7th day of incubation, and after the 12th day, you might even be able to see an embryo moving.

Further Reading: How Duck Eggs Get Fertilized