How to tell boy and girl ducks or ducklings apart

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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 definitively tell boy and girls ducks or ducklings apart!

Entering the search query “how to sex a duck” into Google sounds like something that could land you on an FBI watch list. Fear not. When we use the terminology “sexing a duck,” we’re referring to how you can distinguish between a male vs female duckling or duck, nothing nefarious. And, no, we won’t tell the FBI on you for reading this article.

Adorable ducklings taking a nap. One of the most important considerations for pet or backyard duck parents is the sex of their ducks. In this article, you'll find out how to differentiate between male and female ducks from hatch day through maturity.

Adorable ducklings taking a nap. One of the most important considerations for pet or backyard duck parents is the sex of their ducks. In this article, you’ll find out how to differentiate between male and female ducks, from hatch day through maturity.

Sex vs gender: what’s the difference? 

First, a point of clarity: “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.

Complex organisms are indeed complex, ducks included. And complex biological organisms don’t always line up into neat binary categories, ducks included.

For instance, our female ducks regularly have sex with each other. They also have sex with our drake. Ducks are not known for their sexual discretion, so don’t be alarmed when you see these behaviors in your mature ducks.

Humorously, one of our girls, Marigold (shortened to Mary but pronounced “Ma-wee” since she has trouble with r’s), seems to actually think she’s a drake. She’ll regularly challenge our drake, Sir Winston Duckbill, to a duel. She often wins, sending Winston running for his life.

Even more humorously, some winters Mawy even develops drake feathers (more on that feature below). And while she enjoys mating the other females, she has zero interest in Winston.

We don’t pretend to understand all the genetics, epigenetics, biochemistry, and environmental factors weighing in on Mawy’s gender identity, but her biology/physiology indicates she is a female. (This BBC article may shed some light on Mawy’s circumstances.)

We love this unique, quirky creature regardless and have started calling her Marty (pronounced “Maw-ty”), which she doesn’t seem to find objectionable.

Our son (yes, he's been sexed) performing a bill inspection on Mawy/Mawty.

Our son (yes, he’s been sexed) performing a bill inspection on Mawy/Mawty.

How to sex mature ducks

Sexing certain breeds of ducks at maturity, like Welsh Harlequins, is quite easy to do with your eyes and ears, as you'll read about below...

Sexing certain breeds of ducks at maturity, like Welsh Harlequins, is quite easy to do with your eyes and ears, as you’ll read about below…

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 bull, 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.

How to sex ducklings

While there may be subtle physical differences between sexes of some duck breeds, physical appearance isn't a reliable method of sexing ducklings.

While there may be subtle physical differences between sexes of some duck breeds, physical appearance isn’t a reliable method of sexing 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.

Post-sexing: what next? 

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 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.

For backyard or pet duck parents, we recommend either not having any drakes or having no more than 1 drake per every 3-4 females. Or if you’re not interested in eggs and are instead interested solely in having good pet ducks with lower potential for medical problems, having a small, all-drake flock could be a good choice for you.

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

Now you know how to sex male and female ducklings and ducks, regardless of their age or breed!




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  • Reply
    Jude Crocker
    September 28, 2021 at 9:14 pm

    Hi! I’m Jude and i’m a kid but i do truly love ducks. is it possible that the 2 female ducklings i ordered from Metzer are actually boys?

    • Reply
      Aaron von Frank
      September 29, 2021 at 12:29 pm

      Hi Jude. It is technically possible that Metzer Farms sent you two males instead of two females but it’s VERY unlikely. They’re quite good and experienced at sexing ducklings. We’ve always had 100% sexing accuracy with our Metzer ducks. Is there something happening that makes you think yours are males?

      • Reply
        Jude Crocker
        September 29, 2021 at 11:23 pm

        well, my 6 week old welsh harlequin is developing orange feet and she doesn’t have a black beak yet.

        • Aaron von Frank
          September 30, 2021 at 12:52 pm

          Metzer doesn’t necessarily breed ducks for breed standard, and a secondary sex characteristic such as orange feet in a juvenile doesn’t necessarily indicate the sex of the duck. One thing that will be a dead giveaway for sexing your ducks at 6-8 weeks is the voice. You should be getting some proto-quacks from your ducks if they’re females. The males don’t make the stereotypical duck quacking sound, they sound more raspy and almost frog-like in their vocalizations. Are you hearing the beginnings of quacks in your ducks yet?

        • Jude Crocker
          September 30, 2021 at 5:43 pm

          YES!!! but they dont sound anything like male quack. thank you guys for your attentive looking at comments! You guys are so kind and you helped me SO MUCH with my sweet little ducky girls! God bless you!

        • Aaron von Frank
          October 1, 2021 at 6:52 am

          Glad to hear that, Jude! You’re very welcome. Reach out any time you need duck help. 🙂

  • Reply
    Miranda Rienzo
    July 21, 2021 at 11:03 am

    Hello and thanks for the post, I have a mixed flock of ducks (Rouen , pekin, welsh harlequins and Ancona). We have 2 Ancona and 1 Rouen who are quacking (and I swear the other Rouen was quacking but stopped). All the rest aren’t quacking but don’t sound like the males noise either. They are roughly 7-8 weeks old. Is it possible that they may just develop slower than others or am I unlucky enough to have 7/9 ducks end up being males? One pekin has a drake feather, other one not quite yet, 2 harlequins are completely different colours and can’t tell from feathering. They sound more like they have wheezy peeps still but not that low raspy male sound

    • Reply
      Aaron von Frank
      July 21, 2021 at 12:19 pm

      Hi Miranda! That transitional period is a tough age in which to accurately sex ducklings/ducks. Unfortunately, the only thing you can do at this point (without risking injuring them) is to wait and see. Yes, it is a roll of the dice when you hatch duck eggs or don’t get a sexed run, and some times things don’t come out in your favor. For instance, the very first ducklings we picked out years ago turned out to be 3 males and one female. That’s why it’s often a good idea to order sexed runs unless you actually want to have multiple drakes for some reason (breeding, meat production, etc). Doing so requires separate caged runs and either separate coops or partitions within a coop otherwise they’ll really start going after each other if you have females around to prompt competition for mates. Best of luck!

  • Reply
    May 21, 2021 at 9:10 am

    thanks so much now i know my duckling is male your the best Kevin

  • Reply
    Kevin Scott
    February 1, 2021 at 3:11 pm

    Thanks for the article on sexing ducklings. I have not yet jumped into the pond with ducks yet !
    I currently raise heritage turkeys and chickens.
    I am working towards a small flock of ducks, and while doing my due diligence came upon your site with the article on your bio filtration pond.
    I cannot wait for warm weather – so I can start on the pond.
    I will definitely be following your site.
    Thanks again!

    • Reply
      Aaron von Frank
      February 2, 2021 at 2:06 pm

      Thanks for leaving a note, Kevin! Best of luck in your duck raising ventures, and reach out any time we can be of help. We’re sure looking forward to warmer weather, too.

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