How Are Duck Eggs Fertilized?

Ducks are fun to watch as they swim and play in the water. 

If you are adding waterfowl to your backyard farm, you may be curious about duck egg fertilization. 

Ducks are fascinating birds with interesting mating habits.

Key Takeaway:

Duck egg fertilization occurs when a male duck’s penis penetrates the female’s vagina. The semen then travels to the eggs to fertilize them. The female will lay the eggs and sit on them until they hatch.

This seems like a pretty straightforward process. 

Yet, duck anatomy is more complicated than you might expect. 

Read on to find out how female ducks can choose whether their eggs are fertilized.

how duck eggs are fertilized

Duck Egg Fertilization

Ducks’ eggs are fertilized differently than chicken eggs. 

Ducks can begin mating at around 4 months old. 

Some duck breeds take a little longer, but once a female can lay eggs, she can mate with a male to fertilize her eggs.

Choosing a mate

Ducks do not mate for life. 

Instead, they choose seasonal mates. 

The female will choose a male mate for the breeding season. 

Females outnumber males in the wild and usually in the backyard flock. 

So, they get their pick of a mate.

Female ducks will choose the strongest and healthiest male to mate with. 

Further Reading: Why do ducks bob their heads?

The duck pair will remain monogamous for the season. 

The male will defend his mate from other males, but he will not help raise the ducklings.

In the next breeding season, each duck will choose a different mate to stick with for the season.

On the farm, domesticated ducks act a little differently. 

If a male duck has no other options, he will mate with the same female season after season.

With some species, duck feathers make a big difference in attracting a mate too.

Further Reading: All the Reasons Ducks Have Feathers

Fertilization of the Eggs

Duck males (also known as drakes) have phalluses, and females have vaginal canals. 

This setup differs from most other birds, including chickens, who have cloacas. 

A cloaca is a canal used for both reproduction and defecation.

The drake’s penis is corkscrew-shaped clockwise. 

The female’s vagina is corkscrew-shaped in a counter-clockwise direction. 

This feature of the female duck’s vagina allows her to be more selective about whom she breeds with.

Male ducks perform courting rituals to attract females. 

This helps them bond with the female and eventually get her to choose him.

Yet, many overeager males will mount a female unwillingly. 

Female ducks are subject to rape, so often, their bodies have adapted.

The duck’s counter-clockwise-corkscrew design prevents sperm from reaching her eggs if she is not relaxed. 

The female duck’s vaginal canal also has dead ends where sperm does not meet the eggs.

This allows females to be more selective about which males she breeds.

To accept impregnation, a female duck has to relax her body and lift her tail feathers. 

Further Reading: Ducks wagging their tails and what it means

The penis then penetrates the vagina and delivers sperm to the eggs to fertilize them. 

Then, the duck cycle of life begins. 


When ducks go broody, they begin by building a nest for their broods. 

They can put these nests in interesting and camouflaged locations. 

Ducks are stubborn during the egg-laying process. 

Once they’ve built a nest, they want to stick to it even if it gets moved.

A broody duck may behave differently. 

She will want to stay on her nest most of the day. 

Some days she may eat a ton while others eat barely anything. 

Ducks will sit on their nests for 23-26 hours. 

Further Reading: Why do ducks sit on unfertilized eggs?

Eggs need constant body heat. 

It takes 28 days of incubation to hatch duck eggs because they are much larger than chicken eggs.

Some duck breeds are broodier than others. 

Muscovies are the best brooding ducks. 

They can hatch up to 12-15 duck eggs. 

Mallards, Ancona, and Welsh Harlequins are duck breeds good at brooding.

Duck egg-laying habits vary by breed. 

Duck farmers especially like Khaki Campbell ducks because they are the best-laying ducks. 

They can lay up to 250-340 eggs a year. 

Usually, once you collect the eggs, the female will return to her normal self. 

Other ducks will fight you to protect their nest and eggs.

Further Reading: Why are ducklings yellow?

How Many Male And Female Ducks Should You Raise Together?

In a flock of common ducks, limiting how many male ducks you have per female is important. 

Male ducks compete for female ducks.

If there are not enough females for each male, they become aggressive.

Drakes often mate with a single female roughly and sometimes in gangs. 

This results in injury and sometimes fatality for the female.

With larger duck breeds, duck owners limit the ratios to one male per 5 females. 

In smaller breeds, you’ll get by with 1 male to 10 females.

How Do You Know A Duck Egg Is Fertilized?

Egg candling is the most reliable and safe method of determining a fertilized duck egg.

Do this method five days after the duck has laid these eggs. 

Take the egg into a dark room. 

Hold the candler (a bright LED light) against the large end of the egg. 

If the egg is fertilized, you’ll see a black spot in the center with blood vessels coming from it.

Use this method to monitor the baby duck’s progress. 

Use this to remove nonviable eggs as well as dead embryos.

Can You Eat Fertilized Duck Eggs?

Yes, it’s safe to eat fertilized duck eggs. 

If you are collecting eggs daily, you won’t notice the difference between a fertilized and a non-fertilized duck egg. 

Keep it in the refrigerator, and it should be fine. 

Wash them and eat them like normal.

If you wait a few days between collections, you may want to use the egg candling method. 

This will help you identify if fertilization has occurred.

Crack open the egg to check for fertilization.

If the eggs have been, there will be a dark spot and blood veins. 

Of course, this will result in the death of the embryo.

In other countries, people eat fertilized duck eggs all of the time. 

In places like Vietnam, fertilized duck eggs are a delicacy called Hot Vit Lon. 

Hot Vit Lon is a boiled egg, but the embryonic duck is the meat inside. 

This is a 14-17 day fertilized duck egg.

Many people are squeamish about eating unhatched ducklings. 

Others claim it is a tasty dish. 

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Growing up amidst the sprawling farms of the South, Wesley developed a profound connection with farm animals from a young age. His childhood experiences instilled in him a deep respect for sustainable and humane farming practices. Today, through, Wesley shares his rich knowledge, aiming to inspire and educate others about the joys and intricacies of rural life.

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