An Experiment in Chick Sexing Methods
We’ve all heard them, those crazy methods for sexing chicks that sound too far-fetched to be true. Often, they are not even backed by good reasoning, and so any logical person would chuckle at the suggestion and brush it off as absurd. But so many swear by these methods that one has to wonder, could they possibly work? Anyone who has discovered the addictive nature of hatching chicks could use a simpler and easier way of sexing the many chicks they hatch, right? And why would these methods gather such a following if they did not work?
To test these methods, possibly the best route would be to hatch hundreds of chicks, test all of them, and report the results once they have matured enough to determine their actual sex. Unfortunately, I have neither the time, nor the coop space for such a task. Instead, I will be performing these various methods on as many chicks as I can as I hatch or buy them, and then gathering the data from all of these chicks here over time. Only I will be performing these tests to remove any uncertainty in the uniformity of how tests are performed. Both straight run and sexed chicks may be included here, but because knowing the sex of the chicks beforehand may cause some subconscious skewing, results from sexed chicks will always be reported separately from those of unsexed chicks.
Chick sexing methods were chosen by their commonness, strangeness, or seeming unlikeliness. However, I did have just one ground rule in choosing sexing methods. I decided before I started this experiment that I would NOT do any method that I believe may hurt or cause trauma to any of these chicks. That means I will NOT be lifting them by their beaks, wings, heads, feet, or the backs of their necks, or doing any other method that sounds like it could be harmful to them. To me, enough people have tried these methods unsuccessfully that it is not worth me compromising the health or trust of my chicks just for this experiment. Beyond that, if it seems silly or far-fetched, or it’s very different than any of the other methods I’ve tried, I’m willing to give it a shot! I’m also open to suggestions, so if you have a method that is sufficiently different than the ones already listed on this page, feel free to send it to me in a PM!
Chicks subjected to sexing methods will be of various breeds, all under the age of 4 weeks old when tested. All chicks will be straight run (that is, their sexes were unknown) unless otherwise stated. Subjects are grouped below by hatch date and breed. Subjects from previous broods of chicks will be hidden in 'Spoiler' drop downs to keep the page a bit shorter. Click the blue boxes below to see pictures and more information about previous subjects.
Hatch date: January 4 and 5, 2017
Variety and Breed: Partridge and Red Cochin bantam
Identification: Identified by markings used to distinguish eggs; Abie, Alpha, Lucky, Onesie, and Omega
Hatch date for all of these chicks is assumed to be April 3, 2017.
Variety and Breed: Dark Gray Dorking
Identification: Identified by breed and marker colors added to their heads; DD-Blue, DD-Green1, DD-Green2, DD-Brown, and DD-Purple
Variety and Breed: Red Dorking
Identification: Identified by breed and marker shapes added to their heads; RD-X, RD-O, RD-Dot, RD-Line, and RD-Z. Not pictured is RD-Squirt, who was included in the experiment later. Sadly, RD-Z passed away before its sex could be determined.
Variety and Breed: Black Copper Marans
Identification: Identified by breed and a color spot added to their chests; BCM-Blue, BCM-Green, and BCM-Purple
Variety and Breed: Wheaten Marans
Identification: The only one of this breed and variety, so simply identified as WM
Hatch date: May 12 and 13, 2018
Variety and Breed: Red Cochin bantam
Identification: Distinguished by leg band color, with 'SC' for breed added to eliminate confusion with future chicks
Hatch date: May 21, 2018
Variety and Breed: Mottled Cochin bantam
Identification: Distinguished by leg band color, with 'MC' for breed added to eliminate confusion with future chicks
Hatch date: March 27, 2019
Variety and Breed: Khaki and Fawn Silver Duckwing Old English Game bantam
Identification: Distinguished by the first initial of their leg band color, with 'OEGB' for breed added to eliminate confusion with future chicks
Hatch date: April 19 and 20, 2019
Variety and Breed: White Silkie x Easter-egger mixes and a bantam Cochin x Easter-egger mix
Identification: Identified by the code written on their eggs, B2 (the second blue egg), and G1 and G2 (the green eggs). B2 and G2 are further distinguished by leg bands matching their egg color because of how similar they are.
Hatch date: April 22, 2019
Variety and Breed: Easter-egger bantam
Identification: Easily distinguishable by appearance; one is yellowish and the other is silvery. EEB added to ID for 'Easter-egger bantam'.
Hatch date: April 22, 2019
Variety and Breed: Easter-egger, large fowl ** SEXED PULLETS **
Identification: Easily distinguishable by appearance; one is yellowish and the other is dark brown. EEP added to ID for 'Easter-egger pullet'.
Below, you will find details of all of the sexing methods used in this experiment. The names of these tests is what will be used in tables and figures in the Results section. Due to time constraints, not all chicks have been tested with every sexing method. It will be apparent when a test has not been performed on every chick by the tables and figures in the Results section.
To keep the page a bit shorter, please click the blue box below to open the spoiler and read the different methods. If you're simply returning to check on the results, then you can leave the spoiler closed and not have to scroll past all of the descriptions again!
This is a classic method that is used by big hatcheries, but the thing that people don’t take into account is that it is a trait that must be bred for—not every chick from every source will be accurately sexed using this method! The reason I chose to add this one to the experiment is because so many people spread it as a 100% true sexing method for all chicks. In wing sexing, when the chicks are only a few days old at most, males have a short, even row of pin feathers on their wings, and females have a staggered row of short and long pin feathers on their wings. The picture below (from this thread) shows the difference.
Tail Feather Method
I believe this is an extension of the above method, but I figured it was worth mentioning. In this method, females get their tail feathers in sooner than males.
Tail Tap Method
According to this method, when tapping the chicks on the tail, only males chirp in response and females are silent.
Tail Pull Method
In this method, you gently pull on the chicks’ tails. If they are male, they chirp in response, while if they are female, they are silent.
Needle and Thread Pendulum Method
This is a method that many, MANY people swear by, both for sexing chicks and unborn human babies, too! In this method, you hang a metal needle from a thread above the chick. If it moves back and forth in a straight line, the chick is male. If it makes a little circle with its swing, the chick is female.
Lay on Back Method
In this method, you carefully lay the chick on its back in your hand. If it struggles to right itself, it is male. If it relaxes and just lays there, it is female.
Leg Stretch Method
In this method, you carefully lay the chick on its back in your hand. If it stretches its legs out, it is male, while if it keeps its legs tucked in, it is female. I considered all tests in which the chick consistently kept one leg tucked and stretched out the other to be inconclusive.
Pick Up Method I
According to this method, when a chick is picked up around its body from above and its feet allowed to dangle, a female will pull its feet up and a male will just let its feet dangle.
RETIRED - I believe I may have misinterpreted this test, as literally every chick I've tested has had the same result. I am modifying this test slightly for the upcoming chick season. Please see below for Pick Up Method II.
Pick Up Method II
A modification of the above, but pretty similar. Rather than holding the chicks steady to see if they allow their feet to dangle or hold them up, I will instead be checking to see if they pull their feet up or allow them to dangle as they are being lifted.
In this method, you surprise the chicks in one way or another and gauge how they react. Many people suggest throwing a hat into the brooder, but one can also make a loud noise, BRIEFLY flap a flag or cloth over the brooder, or any other method that might surprise the chicks. If a chick stands up or stays where it’s standing, it is male. If a chick ducks down or runs for cover, it is female. For this experiment, I made a loud noise.
String Peck Method
In this method, you dangle a piece of string in the brooder. If a chick pecks it twice or more, it is male. If it pecks the string only once or is disinterested, it is female.
Pick Up Chirp Method
According to this method, when picking up a chick, only the males chirp indignantly. Females remain silent.
Tail Fan Method
For this method, you must wait until the chicks have tail feathers. When holding them, if you tip them forward suddenly, only females fan their tail feathers. Males don’t move their tails.
Penny Toss Method
For this method, you rub a penny on the back of the chick in question, and then flip the coin. If it lands on heads, the chick is male, and if it lands on tails, the chick is female.
Vinegar Water Method
According to this method, when offered a dish of plain water beside a dish of white vinegar water (at the rate of 1 tablespoon white vinegar per 8 ounces of water), males will prefer plain water and females will prefer vinegar water. To make sure the water was the only thing the chicks were deciding on, I used identical dishes with identical amounts of fluid in them.
Vent Shape Method
According to this method, male and female chicks have different vent opening shapes. This is not the same as vent sexing, which requires one to know the difference between the internal part of the vent, but is instead simply looking at the shape of the vent from the outside. Males have small, round vent openings and females have wider, oval-shaped vent openings. Because this can vary a bit, I compared like breeds to like breeds for vent shape.
Comb Length Method
This method states that chicks whose combs end at or past the front edge of their nostrils are male, and chicks whose combs end before there are female. See this thread for more details: Comb Sexing Chicks
Wing Split Method
According to this method, at approximately one week old or when wing feathers have only just come in, males will have a distinct gap or split between the primary and secondary wing feathers, while females' wings will be lacking this gap. The below images show what I considered to be a split and the lack of a split in one-week-old chicks' wing feathers.
Egg Shape Method
I am putting this one last because I will not be able to use this method on all chicks. By this method, males hatch out of narrow, pointy eggs, and females hatch out of shorter, rounder eggs from the same hen. All eggs hatched through 2018 were "eyeballed", not measured, and compared to one another, not to just any other egg. This method was used because I believe that's how most backyarders tend to do this test.
However, for 2019 and beyond, I was able to get my hands on calipers to measure eggs with for a bit more scientific of an approach. All eggs from the same hen are measured for length and width, from which a ratio (in the form of a number between 0.5 and 1.0) is calculated by dividing the width by the length. From these ratios, an average is calculated for the hen. Because the closer to 1.0 a ratio is, the more similar the length and width are, meaning the more round the egg is, anything above the average is considered round, while anything below it is considered pointy. Anything equal to the average by at least 3 decimal places (the certainty at which the calipers measure) will be considered 'inconclusive'.
I will not be selecting eggs based on shape for this method (in other words, I will incubate eggs regardless of their roundness or pointiness), but I will record the egg shapes of each egg and track which chick hatches out of which egg.
You can view all of the raw data and results on this Google Spreadsheet. There are tabs at the bottom to switch between results by test and results by chick. Please note that I will not add any chick's results to the 'results by test' tab on the spreadsheet OR to the below graphs until their sex is confirmed! I will, however, put them in the 'results by chick' section in the spreadsheet as a means of recording the data until results can be confirmed.
The spread of male, female, and inconclusive predictions by test for straight run chicks. At minimum, 11 chicks were tested in each method, and at maximum there were 34 chicks tested. On the right is the actual ratio of males and females so far.
Accuracy of each test on straight run chicks is depicted in the below graph showing the percentage of correct predictions by test. Again, some tests were performed on more chicks than others, with a minimum of 11 and a maximum of 34 chicks so far.
The below graphs show the percentage of correct predictions made by each method, separated by breed. Only straight run chicks are included in these graphs. When separated out by breed, more tests were able to achieve exactly or close to 100% accuracy. However, sample sizes are still small (as few as 5 chicks in some cases), and so these results should not be taken as law.
Bantam Cochins - As many as 14 and as few as 5 chicks were tested for the percentages in the below graph.
Dorkings - As many as 10 and as few as 9 chicks were tested for the percentages in the below graph.
Marans - As many as 10 and as few as 5 chicks were tested for the percentages in the below graph.
The below graphs show the spread of male, female, and inconclusive predictions for sexed chicks, as well as the percentage of correct predictions on sexed chicks. Only 2 sexed chicks have been tested so far, so these results should not be considered strong evidence of anything at this point. Note also that no sexed chicks so far have been tested for the accuracy of egg shape, and so that test has a 0% accuracy rating only out of lack of any tests performed.
- No method was 100% accurate on straight run chicks, except for when results were separated by breed. However, when separating by breed, sample sizes become very small (as few as 5 chicks per breed), and so that data is not very strong evidence of anything yet.
- The Needle and Thread, Surprise, and Vent Shape methods are tied as the most accurate tests at 65% accuracy on straight run chicks.
- So far, the Pick Up method has had consistent reactions of all chicks tested, with a few other methods having nearly consistent reactions with one or two chicks differing from the majority. This would imply that they are all or mostly all the same sex if those methods were true. This also implies that all or most chicks react in the same way to these tests, not based on their sex.
- Several tests also had unanimous or nearly unanimous reaction in all chicks of the same breed, suggesting that they are related to breed and not sex.
- Comb Length was the most inconclusive by a tiny margin, with 6 of the 34 chicks (or 17.65%) having inconclusive results. This test has a large gray area where comb length appears past the nostril at one angle, but not at another angle, and so it is difficult to record conclusive results on some chicks. Some practice has improved my ability to conclude male or female on more recent chicks, however.
- Leg Stretch was the second most inconsistent, with 5 out of the 29 chicks tested (or 17.24%) stretching one leg out while tucking the other in. Some say that even when only one leg is stretched out, this still means the chick is male. In this case, the accuracy of that test would rise from about 31% to about 41.4%.
- Reversing the male and female reactions on the lowest accuracy tests raises a few of them up to come close to, tie with, or even surpass the most accurate tests, as detailed below.
- If the Leg Stretch method is reversed so that chicks that stretch out their legs are considered female and chicks that tuck in their legs are male, the accuracy of that test is instead 51.7%.
- Since some consider chicks who stretch one leg out and keep one leg in to be male, the accuracy of the test would rise to 62.1%. If we are reversing the male and female reactions, however, these one in, one out chicks would be considered female, meaning the accuracy of the test would end up being 58.6%.
- In the String Peck method, if chicks who peck a string more than two times are considered female and chicks who peck it less or are disinterested are considered male, the accuracy of that test rises to 70%, making it the most accurate method.
- If, in the Penny Toss, heads means female and tails means male, the accuracy of that test rises to tie with the current most accurate tests at 65%.
- If, by the Egg Shape method, males hatch from round eggs and females hatch from pointy eggs, that test becomes 63.6% accurate. However, only 11 chicks have been tested using this method, and so its results are not as strong as others.
- If the Comb Length method is reversed so that females have combs stopping past the end of the nostrils and males' combs stop before the end of the nostrils, its accuracy rises to 47.1%.