How to sex ducks & ducklings: male vs female

Last Updated on March 9, 2023 by Aaron von Frank

There are lots of reasons you may want to know whether you’ve got male or female ducks or ducklings. In this article, you’ll find out how to sex ducks, regardless of breed or age!

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Use the table of contents below to jump right to the section you’re interested in or read the whole article for a deeper dive. 

Table of contents:

Part 1: What does “sexing a duck” mean and why is it important?
Part 2: How to sex MATURE ducks
Part 3: How to sex DUCKLINGS
Part 4: Duck sexing frequently asked questions

Part 1: What is “sexing” a duck? Why is it important? 

“Sexing a duck” is the process of distinguishing between a male vs female duckling or mature duck. 

Knowing the sex of a duck is a very important consideration for anyone considering raising ducklings or adopting mature ducks. That’s because mixed-sex flocks can be much more difficult to manage, leading to more fights, over-mating and other problems. 

(See: Should you get male or female ducks or both?)

So how do you tell the difference between male and female ducks regardless of age and breed?  

Part 2: How to sex mature ducks

Let’s start with the easy part: sexing 6+ week old ducks:

Method 1. Vocalization check

If you’ve ever raised ducklings, you know they mature incredibly quickly. In fact, they look like miniature adults after about six weeks. At that point, you can start to tell the difference between male and female ducks using your ears.

That’s because real duck men don’t quack. Instead, drakes make more of a low, raspy blurp-blurp-blurp sound. A drake could talk as loud as it wanted in your backyard and would likely be unable to let your neighbors in on the conversation — unless you have particularly nosy neighbors.

Only female ducks make the distinctive (and loud) duck vocalizations that you think of with ducks: quack-quack-quack. Granted they actually have a far more varied and nuanced vocabulary than “quack.” When a female duck wants to be heard, your entire neighborhood will know about it.

Vocalizations are an easy way to sex either:

a) Young 6-10 week old ducks who haven’t yet earned their distinctive adult plumage. (*Watch the video “Duckling vocalizations: 12 Days old to 6 weeks old” in our How to raise ducklings guide.)

b) Monomorphic breeds like American Pekins who have nearly identical plumage regardless of their sex.

Method 2: Plumage and other physical features

Feather coloration – For older, mature ducks with dimorphic plumage (e.g. the males look different than the females), the easiest way to sex them is to look at their feathers. Drakes of most mallard-derived breeds have gorgeous green-iridescent head plumage for a large part of the year (nuptial plumage), until they go into their eclipse plumage when they look far less showy.

Female ducks within these breeds do not have green heads. However, for other breeds like Pekins (which are all-white), this distinction does not help in sexing. 

(Learn more about duck plumage and molting patterns.)

Drake feathers – While in their nuptial plumage, drakes also have “drake feathers,” a few curled feathers on the top side of their tail.

Female ducks do not have curly drake feathers on the tops of their tails.

Other physical features – Finally, some breeds — like our Welsh Harlequins — also have other physical differences at maturity. For instance, our Welsh Harlequin drake has bright orange legs and a yellow/orange bill, whereas our females’ legs are more dark grey/green in color as are their bills. These physical distinctions are not universal to all breeds of ducks.

Using the distinctions detailed above (vocalizations, plumage check, & other breed-specific sex differences), you should be able to sex a duck that’s 6+ weeks old. If you’re trying to sex a monomorphic breed, there won’t be a green head to go by, but the voice and possibly the drake feather (if they’re in nuptial plumage) will indicate their sex.

Part 3: How to sex ducklings

Now comes the harder part: sexing those adorable little duckling fuzzballs that all look nearly identical.

Methods: Down color vs bill color vs vent sexing 

In some duck breeds, there are subtle differences in down coloration between male and female ducklings. There are too many breeds and too much variability (or lack of variability) to list here. Plus, this method is not going to help you definitely sex ducklings.

As for bills: in very young Welsh Harlequin ducklings (days 1-3), a pinkish colored bill with a dark tip likely means female, whereas a darker bill likely means male. However, this method is not definitive either and only applies to one breed of duck.

The only 100% definitive way to sex ducklings of any breed is vent sexing, also called vent checking. However, it’s critical that you know how to do vent sexing safely and correctly before you give it a try. And as John Metzer of Metzer Farms says, vent sexing is best done on 1-2 day old ducklings — after that, it’s more difficult.

Warning: you can permanently injure your ducklings with improper vent check

Before we dive into the how to’s of vent sexing, we need to issue a very clear warning. If a vent check is done incorrectly with too much force or for too long a duration, you can permanently injure your ducklings. Those little parts are quite delicate!

Thus, if you don’t know how to conduct a proper vent check, please do not proceed. Let an expert — such as an avian vet — conduct a vent check for you and possibly teach you how to do it for future reference.

Vent sexing instructional video

There are also excellent online instructional videos about how to sex ducklings. We’d highly recommend watching this Metzer Farms’ video about vent checking before you consider doing the procedure yourself:

*For reference, Metzer Farms sexes tens of thousands of ducklings per year, so they likely have more experience sexing ducklings than anyone else out there.

How to vent sex ducklings:

A duck’s anal vent, aka cloaca, is where their reproductive organs reside. However, in ducks/ducklings, neither the male penis nor the female vagina is visible with a mere surface inspection. Hence the need for a deeper look…

When doing vent sexing, you’re NOT trying to pop the [potential] drake’s penis out by pushing on the area around the vent. Instead, holding the duckling upside down in one hand, use the fingers of your other hand to gently pull back (not pushing or applying pressure) on either side of the vent in order to open the vent and expose the reproductive organs below.  

Note: Your first time out, this process may be easier with two people — one to securely hold the duckling, the other to do the penis hunting (ha!).

If you spot a drake penis (which looks like a small, light-colored worm), you’ve got a male. No penis = female.

If you’re vent sexing a bunch of ducklings, you should end up with about a 50/50 ratio of males to females. If not, you’ve likely not been very accurate your first time around. If so, don’t feel bad – it takes a lot of practice to get really good at vent sexing.

Part 4: Duck sexing frequently asked questions

Now you know how to sex male and female ducklings and ducks, regardless of their age or breed! Here are a few more followup questions we’re often asked: 

How do you keep track of male vs female ducklings after you’ve sexed them? 

Are you hatching your own duck eggs? If you want to keep track of your male and female ducklings after sexing them, you can either:

a) separate them into separate “flocks” immediately after sexing, or
b) keep both sexes together, but place a zip tie (not too tight) around the ankles of one of the sexes, clipping off the excess tie.

Warning: If you use zip ties, you have to pay very careful attention as the ducklings’ ankles grow so you don’t end up cutting into the skin with the ties. Remove and replace zip ties as your ducklings grow.

What’s the ideal ratio of male to female ducks in a backyard flock?

For backyard or pet duck parents interested in egg production, we recommend either not having any drakes or having no more than 1 drake per every 3-4 females.

If you have more than one male, plan on keeping them separated for most of the year to prevent fights and injuries. (Yes, we know this from experience!) 

Not interested in eggs? Want to raise ducks for meat production? Or are you instead interested solely in having good pet ducks with lower potential for medical problems?

Then having all drakes could be a good choice for you. Without any females around, males are also far less aggressive.   

Read more on this topic in our article: Should I get male or female ducks… or both?

Sex vs gender: what’s the difference? 

“Sex” refers to reproductive organs. “Gender” refers to a critter’s sexual identification, e.g. primarily a function of the brain. Confusingly, these terms are often used interchangeably even though they’re quite different, biologically speaking.

We and many other backyard poultry owners we’ve spoken with have had curious and humorous situations wherein their female ducks and chickens seemingly start to look and act like males. 

For instance, our duck Mary (who we now jokingly call Marty) even has the secondary sex characteristics of a drake: green head during nuptial plumage, orange feet, and curled drake tail feather. What the heck?

What’s the cause of this phenomenon? Turns out due to prolific egg laying in years past, Mary/Marty experienced ovarian damage. With non-functioning ovaries, her body stopped producing the hormones that made her female, so she started to revert to the default sex in ducks/birds, which is male.

Mary’s sex is female, based on her reproductive organs and chromosomes. What’s her gender? We have no idea because she’s a duck with a relatively simple brain and she’s not saying. Her flock doesn’t seem to care, but she and our drake (Sir Winston Duckbill) tend to get in a lot of scuffles, thus requiring physical separation via fencing.

See: Can ducks change sex? The curious story of Mary/Marty the duck

Thankfully, when it comes to sexing ducks (or ducklings), most cases aren’t nearly as difficult as Mary/Marty, as you’ve learned from this article! 

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Want to see a video summary of this article? Check out our Google web story, how to sex ducks and ducklings!

KIGI,