Sexing Day-Old Chicks: How to Identify Pullets and Cockerels

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Sort your baby chickens based on wing feathers, sprout patterns, genetic markers in down coloring or vent sorting.
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TOP. Open vent. The interior border is rolled back and genitalia is exposed. Chick is a pullet (no bulb protrudes at lower brim). ABOVE: Whoops! Chick defecates as author spreads vent.
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TOP: The hand scoop. Chick is picked up with left hand . . . its head between 3rd and 4th fingers, legs between 4th and 5th. Rump ducktails up. ABOVE LEFT. Evacuating the chick. Left thumb pushes on lower abdomen. ABOVE RIGHT: The vent spread. Left thumb presses left edge of vent up and over so that interior border is turned towards chick's back. Right thumb and finger are ready to pinch back right edge of vent.

Although J. Mulder and O. Wollan (January/February 1974) swear that they raised 23 pullets from 23 eggs by comparing the shape of their hen fruit (according to them, eggs that eventually hatch into pullets are more oval than the pointy eggs that eventually hatch out as cockerels) . . . other chicken raisers disagree — sometimes most emphatically — with this bit of barnyard wisdom. 

“The fact is,” says Veronica Waters (of Wellton, Arizona), “that one hen will lay an egg of almost identical shape every day. This shape also differs from one breed to another. Therefore, the egg’s form cannot indicate the sex of the chick it will produce. If it did, all the layings of a particular fowl–or of a particular breed or strain–would be of one sex. Common sense, or any familiarity with chickens, will tell you that this is not so.” 

So there you have it: both sides of The Controversy. Some say that you can sex chickens by the shape of the eggs from which they’ll hatch . . . some say you can’t.

Beth Bosk, on the other hand, says, “To heck with the whole argument. The only way to really sex chickens is to let them hatch first . . . and then sort the males from the females.” 

There are several ways to do this picking and choosing (some are considered by professional chicken sexers to be closely guarded trade secrets) . . . and Beth has doen a sterling job of ferreting them out. As nearly as we can make out, some of the information in the following article has never appeared in print in a general interest magazine — or even a specialized trade publication — before. 

Vent Sorting

Lyle Scheline is a professional chicken sexer, an expert of 22 years’ experience. On hatch days he shows up at the A & M Hatchery, rolls up his white shirt sleeves and stands at a wood table under a suspended light.

Box after box of hatchlings (some but an hour old) are brought in and placed before Lyle at waist level. Over and over he scoops up a chick with his left hand, expels its droppings with a squeeze of his thumb, opens its vent with his fingers, peers through the magnifying lenses attached to his spectacles and determines its sex. Then he deposits the tiny bird in one of two bins. Two thousand vent sexes and a good day’s work later, his hands and his shirt front are still immaculate. And if you buy sexed chicks from Lyle’s employer, the sort is guaranteed 95 percent accurate.

In slow motion, here’s how Scheline separates those chicks.

There are three cardboard boxes on the table: one in front of Lyle (full of unsorted hatchlings) and the pullet and cockerel bins to right and left. Each container is divided into four compartments to buffer the shock of long-distance travel when the young birds are shipped the next day. A milk carton, its top removed and two adjoining sides cut down halfway, stands behind the “unsorted” container with the low sides angled to face front.

With his left hand Lyle scoops up a chick, catching its neck between his middle and ring fingers and its legs between his ring finger and pinky. In one swoop the ball of fuzz is perfectly balanced and duck-tailed rump up.

In chickens — as in other birds the intestinal and genitourinary tracts both empty into a common cavity known as the cloaca. Before this area can be examined, the chick has to be evacuated (rid of the blob of umbilical dinner that remains in its lower intestine). Lyle holds the chick toward the milk carton and squeezes its lower abdomen once with his left thumb. A small amount of feces squirts into the container, and Scheline finishes the job quickly before another mess erupts.

The chick — still held in the same grasp — is raised close to Lyle’s face, and his left thumb presses the left edge of the vent up and over so that the interior border is turned toward the bird’s neck and secured in that position. A fraction of a second later, Scheline’s right thumb and first finger spread apart the other half of the orifice. The margin is folded down toward the abdomen and held there with a firm pinch. The aperture is then fully open (wide from back to belly, narrower thigh to thigh) and it’s possible to peer inside. Some sorters use the right index finger to test the tissues for elasticity. Lyle, however, depends entirely on making a visual check with his eyes.

Vent sexing is based on the fact that the hatchling cockerel has a rudimentary sex organ called the “male process” . . . a very small, glossy, transparent bulb that protrudes from amid the second of three cloacal folds inside the cavity. The structure is independent of the surrounding tissues and pokes out almost as far as the vent opening when the border is pushed down far enough for examination. If you’re not farsighted, you can see the process with the naked eye. In contrast, the typical female chick has a shallow depression — or just a trace of swelling — at the same site.

So far, so good . . . but here’s the catch: One day-old cockerel out of five isn’t so distinctly characterized. He has a smaller bulb, a flat bulb, a bulb that protrudes downward instead of up or a grooved bulb that looks more like a fold than a male process.

More confusing still, 40 percent of day-old pullets have organs that resemble those of the males. This happens because embryos of both sexes start out with male-like bumps. In the majority of females, the process begins to shrink by the second week of incubation and has vanished by hatching time. Not so, however, with two pullets out of five. Their lingering protuberances are usually smaller than cockerels’, but are sometimes as large as the average male bulb.

As the female grows older, the process will continue to regress . . . just as the questionable male organs will extend and grow larger. But you can’t wait more than a day or two to vent sex a chick. It has to be done before the youngster eats and thus distends its lower alimentary tract.

Fortunately, the trained eye can still discern differences between the true male process and the female protuberance at hatch. The cockerel’s organ (whether regular, small, flat or divided) consists of compact, lustrous tissue that continues to hold its shape when exposed. The female bulb even a large one — is less conspicuous and lacks sheen and elasticity. When the vent is spread apart and the process revealed, the pullet’s bump doesn’t hold but fades away in seconds. If the bulge is touched, it will depress.

Accordingly, when Lyle sees a shiny bulb-shaped process protrude to the vent’s lower edge and stay put, he plops the chick into the cockerel bin. And if the same area bears a shallow depression, just a trace of dull protuberance or a larger bulb that fades away, he plunks the bird — with a somewhat wider smile — into the pullet container. The occasional case he’s unsure of goes back into the unsorted box to be examined again later. The cloacal folds rearrange in the meantime, and the process becomes easier to sex.

Lyle Scheline’s large, blunt fingers and make-light-of-it modesty belie the deftness and coordination necessary for his fast, decisive skill. Undoubtedly, though, vent sexing does take a knack. The sorter must be firm and gentle simultaneously: If the chick is held too tightly, it will weaken and later die. Lyle knows sexers who work a third again as fast as he does — employing a different hand scoop — but their hatchlings don’t always survive. Yet you can’t be too queasy about hurting the little birds, or you’ll never get their vents open far enough to expose the phallus and will end up trying to make guesses about the upper cloacal folds.

Speed is important too. If you’re not swift about completing the check — or if you press down on the lower part of the abdomen as you pinch back the right edge of the vent — another glob of feces will erupt and coat the cavity. When that happens, you blot the area.

Nevertheless, I’d say that any nimble-fingered homesteader could vent sex a good 75 percent of his day-old chicks, without an instructed apprenticeship, just by knowing what to look for and how to spread the aperture. (The other 25 percent of discriminations probably do take a tutored eye.)

If you want to learn the art, it’s best to put your fingers through the motions of hand scoop and vent spread before you try to sex a live bird. Dime stores carry little rubber replica chicks intended as babies’ bathtub toys. Buy one, magic-marker a small circle at the appropriate place and practice.

As a novice chicken sexer myself, I find that the most difficult manipulation of the technique is evacuation of the chick with the left thumb. Only rarely do I find that exact spot on the lower belly which relaxes the sphincter when pushed. What I do instead is sex my hatchlings over a large laundry tub.

The problem is that if the chick isn’t evacuated beforehand, the feces seep into the cavity as you spread the vent apart. This isn’t the clean-cut eruption the thumb press effects: It drips, I blot . . . it squirts, I blot . . . and again, until the aperture is clean and I can peer in. This procedure takes more time and is certainly messier, but it works. When I’m done, the toilet paper goes in the wastepaper basket and I turn on the tub faucet and flush the rest of the droppings down the drain.

Down Color Sorting

Not all chicks have to be vent sexed: A variety of crossbreeds can be sorted out by the color and markings of their down. In these cases the juvenile coloring is a sex-linked characteristic . . . that is, the pullets’ coloration is determined by mama’s gene, the cockerels’ by pa’s. The most important factor to remember about these pairings is that the method doesn’t hold if the breeds of hen and rooster are switched.

1.Gold breed roosters mated to silver and penciled breed hens produce buff or red females and cream, white or smoky males. Either sex may or may not show narrow striping.

Gold breed roosters include Rhode Island Reds and the buff varieties of the following breeds: Leghorn, Minorca, Wyandotte, Plymouth Rock and Cochin.

Silver and penciled hens include; White Wyandotte, Columbian Wyandotte, Silver-laced Wyandotte, Silver-penciled Wyandotte, Columbian Plymouth Rock, Silver-penciled Plymouth Rock, Light Sussex, Light Brahma and Dark Brahma.

In addition, Brown Leghorn, Partridge Wyandotte, Partridge Plymouth Rock and Golden-laced Wyandotte roosters can be crossed with Columbian Wyandotte, Columbian Plymouth Rock, Light Sussex and Light Brahma hens to produce chicks with the same sex-linked distinctions.

2.Barred Rock hens crossed with any brown-head rooster, or with any black or buff variety, produce black males with white head spots and yellow beaks, shanks and toes. The female chicks are all black above with dark beaks, shanks and toes. The same offspring results from the crossing of a BarredRock hen and any recessive whiterooster –White Wyandotte, Langshan, Minorca or Dorking–with the exception of the recessive White Plymouth Rock.

Incidentally, three “pure” or standard breeds produce chicks that can sometimes be sorted on the basis of their down markings. One of these is the Barred Rock . . . hatchlings with yellow head spots are males. Both sexes of New Hampshire and Buff Orpington chicks generally hatch totally buff. Some, however, have a black head spot and are pullets. Others may have off-white streaks through the buff down at the upper wing joints (shoulders), and these are cockerels. The male marking is more common than the female, but is also more difficult to detect.

Before Lyle overhauls a box of buffs, he “sight-sexes” them quickly for markings. The darkest buff chicks tend to be males, but — since that isn’t always true — each hatchling of that color goes through the vent check.

Wing Feather Sprout Pattern Sorting

The A & M Hatchery, like others, stocks two popular hybrid chickens — the meaty Cornish White Rocks and the super layers known as Hi-Line White Leghorns — that have been specially developed to allow sexing from the pattern made by the feather sprouts on their wing tips at hatch.

Two chicks at a time, one wing in each hand, Lyle spreads out the wing tips with his fingers and reads the code . . . which is just as regular as visual Morse. If the bird is a cockerel, the feather sprouts are all the same length and make a tall, straight bow line. A pullet, in contrast, shows an alternating tall boxshort box pattern.

Sorting by Occurance of Wing Feathers

Sorting on the basis of sprout patterns is possible only for chicks of specially selected hybrid stock . . . and carefully controlled liaisons aren’t characteristic of the casual homestead chicken yard. There is, however, another wing-feather sort that any fumble-fingered back-to-the-lander can employ to sex his own brood. This is the simplest and easiest non-vent system, and also the one that can be used with the widest variety of flocks. Here’s how it works:

Any Mediterranean breed rooster (all varieties of Minorca, Leghorn, Spanish, Andalusian, Ancona and Buttercup) let loose with any American breed, Asiatic breed or English Orpington hen (includes all varieties of Plymouth Rock, Wyandotte, Java, Dominique, Rhode Island Red, Rhode Island White, Buckeye, Chantecler, Jersey Black Giant, Lamona, New Hampshire, Brahma, Cochin, Langshan and the Orpingtons) produces pullets that hatch out with their wing feathers well developed and clearly in sight. By the end of the first week, the small female chick even has a squirt of tail. Cockerels hatch out either with no wing feathers or with just a touch of sprout at the tip. You have about a week and a half to make the distinction . . . the rate of feathering evens up after that time.

A Note of Thanks: I’ve found chicken sexing (even at the novice level) a great convenience in managing my own flock, and I’m glad to have learned the skill . . . especially after two years of searching for a hatchery that would let me watch a professional sorter at work. I’d like to express my gratitude to Robert Atkins, owner-operator of the A & M Hatchery in Santa Rosa, California. And my deepest appreciation goes to Lyle Scheline, who slowed down long enough to teach me finger by finger.