You got a bunch of straight run muscovy ducklings, and probably want to figure out if you have males or females so you can get a correct gender ratio going on, hopefully preventing blood feuds from occurring once the males, if there are any, hit puberty and start fighting over girls. Muscovy ducklings, like regular ducks, can be vent sexed when they hatch up until a few days old. If a penis is seen, it’s a boy, if it isn’t, most likely it’s a girl.
However, due to the fact that it’s possible to hurt the ducklings, vent sexing is not recommended unless you have experience doing so or have someone to walk you through it.
Sexing Adults
Adult ducks are easy to sex by sight and sound. Males have much more caruncles (the red warts on their faces) than females, and can only make huffing and hissing sounds, while females can do all that and trill. They also occasionally make their own version of a “quack”, but they sound more like someone squeezed a dog squeak toy than a duck’s quack.
Male muscovies are also larger in size–sometimes almost double. They are also unable to fly due to their weight, while females are able to lift off the ground.
Sexing Ducklings
Prior to their wing feathers coming in at around 13 weeks, the most reliable way to sex ducklings is through vent sexing. However, if you can’t do that, then size of the ducklings is the next best thing. Male ducklings on average will be larger than female ducklings–they have larger feet, breasts, and longer bodies (see photo below for comparison.) Males will be longer from their legs to the tip of their tail than females, and this trait shows up as soon as their tail feathers begin coming in. Their bills are also going to be bigger and rounder in comparison.
At around 8-11 weeks (depending on what they’re eating and how fast they’re growing—free ranged birds that get less chick feed/gamebird feed grow slower) is when you can reliably sex them through their primary wing feathers. The females will begin developing their primary feathers (the longest flight feathers) almost a week to two weeks ahed while the males will not until the ducklets are already fully feathered.
Notice the primary feathers are still pins while the ducklet already
has her’s fully formed.
Hope this was helpful in determining the gender of your ducklings!
Vent Sexing Day Old Ducklings
Warning: Do not attempt without someone to show you first
The most accurate way (other than the wings and tail when they are older) to sex ducklings is vent sexing. It should be done when they have fluffed out, the first 3 days being easiest since it’s control over holding it in would not be as strong.
I hold them firmly upside down with their bellies facing me in one hand, my pointer finger pushing the tail back, and with the thumb and the forefinger of my other hand on either side of the vent, gently spread the cloaca apart (DO NOT PUSH DOWN–you are not trying to “pop” anything out in the traditional sense). After a few seconds, the duckling may relax it, and when it chirps, should have some bearing down motion which helps invert the cloaca. If it’s a boy, a penis will be visible/pop out, if not, it’s a girl.
There’s a possibility that the duckling may hold it in, in which case you could misidentify the gender.
Afterwards, make sure the duckling has retracted the vent, if not, you can gently massage it back.