Put in the day they hatched and the breed, and get the window her first egg is likely to fall in — the hatchery’s own figure for that breed, and the three general answers, which do not agree. Then the one thing that moves her inside that window: how long your days are when she comes of age.
Rhode Island Red
First egg: most likely …
Every published window, as dates for your hatch
Your days when she comes of age
The signs she is close
When to switch to layer feed
A pullet that is hunched, off her food or straining is a question for a vet, not for a calendar.
Laying rules checked 2026-09-25; the breed figures are Meyer Hatchery’s, checked 2026-09-22.
Quick answer: most pullets lay their first egg somewhere between 16 and 26 weeks old, and the sources do not agree on exactly where: the University of Wisconsin says 18 to 22 weeks “during ideal day length”, the University of Minnesota says around six months, and Meyer Hatchery says 16 to 24 weeks in general and gives each breed its own range — 16 to 20 weeks for a Rhode Island Red, 20 to 24 for a Buff Orpington. What moves a pullet inside that range more than anything is the length of the day when she comes of age. This calculator turns your hatch date into those windows, as dates, and tells you how long your days will be then.
Why you get three answers, and a range each time
Nobody publishes a date, because there isn’t one. Every source gives a span of weeks, and they are measuring slightly different birds in slightly different conditions. Wisconsin’s 18 to 22 weeks comes with a condition attached — “During ideal day length (14-16 hours of light) and with adequate nutrition, housing, and management” — which most backyard pullets in autumn do not get. Minnesota’s “around six months” is the plain answer for an ordinary backyard hen. Meyer’s per-breed figures are the hatchery’s own, for its own birds, and they vary a lot: a New Hampshire Red at 12 to 16 weeks, a Light Brahma at 24 weeks or more.
So the calculator leads with your breed’s own figure where the hatchery publishes one, shows the three general windows underneath it as dates, and never averages them into a number nobody published.
Daylight: the thing that moves her most
Chickens lay by the length of the day. The University of Kentucky: “Chickens are called long-season breeders, meaning that they come into production as days become longer.” The University of Maine is more precise: “a light-day of 11 to 12 hours will initiate egg production.”
That is why the same breed, hatched two months apart, starts at such different ages. A pullet hatched in spring comes of age in autumn, as the days shorten — and Maine says that is no bad thing: it “slows ovarian development and allows the female to complete her skeletal growth before the rigors of egg production.” If her window lands in November or December and your days are under 11 hours, she may simply wait for spring. The calculator works out your day length on the date she reaches her window, from your latitude, and if it is under Maine’s figure it tells you the date your days are back over 12 hours. That date is astronomy, not a promise about your hen — but it is the one to watch.
A pullet hatched in late winter comes of age in lengthening days, and the risk runs the other way: she can start too young. Maine: “Allowing young pullets to begin laying before they reach 17 or 18 weeks of age is unwise and may produce a condition known as prolapse.” Kentucky adds that early layers “may lay smaller eggs throughout the production cycle.”
Should I add light to bring her on?
You can, and Maine’s bulletin says how: “pullets should be on a schedule of increasing light by the time they are 20 weeks of age. For the heritage breeds, it may be preferable to wait until 22 weeks of age.” Add it slowly — Kentucky: “slowly increase the light exposure until they are exposed to about 14 hours of light per day” — and hold it, because “Laying birds must never see a drop in day length.” Plenty of keepers deliberately let young hens wait for spring instead. Tell the calculator which you are doing and it gives you the date to start.
The signs she is close
- Comb and wattles. Meyer: “A pullet’s comb and wattles will enlarge and turn bright red in color when she’s nearing point-of-lay.” Maine explains why: a hormone from the ovary causes “the reddening and waxiness of the comb and wattles.”
- The squat. Reach towards her back and she crouches with her wings out — the posture a hen takes for a rooster.
- Nest boxes. Meyer: “Within a week or two before the onset of laying, you may see a pullet jump into the nesting boxes and check them out.” A dummy egg or a golf ball in the box shows her where it goes.
- The pubic bones. Mississippi State’s check, for when you can pick her up: in a laying hen the two small bones either side of the vent are “flexible and wide apart, with at least two finger widths between them”; before lay, “one finger width or less.”
When to switch to layer feed
Not before the signs. Kentucky is blunt about it: “do not feed a layer diet to growing chickens. The diet of a laying hen is high in calcium, which is needed for the production of eggshells. This level of calcium, however, is harmful to non-laying chickens.” Meyer’s rule for when: “When you begin to see the first signs of a pullet who is nearing point-of-lay, switch their diet over to a layer ration that contains calcium.”