Kailan mapipisa, at ilang sisiw ang aasahan?
Twenty-one days is the easy half. The table below is the harder one: ten eggs under an inahin come out as about five and a half weaned sisiw, and every day the eggs sat on a shelf past a week takes more off that.
One flock, worked all the way through
The answer for these numbers
- Hatch date
- 2026-09-03
- Candle between
- 2026-08-20 to 2026-08-23
- Stop turning on
- 2026-08-31
- Running late by, hours
- 5
- Hatch rate after storage, %
- 76.4 (63.0 to 89.9)
- Chicks hatched
- 9.2 (7.6 to 10.8)
- Chicks weaned
- 6.1 (3.5 to 9.4)
| Eggs set | Chicks hatched | Chicks weaned |
|---|---|---|
| 6 eggs | 4.6 (3.8 to 5.4) | 3.1 (1.8 to 4.7) |
| 8 eggs | 6.1 (5.0 to 7.2) | 4.1 (2.4 to 6.3) |
| 10 eggs | 7.6 (6.3 to 9.0) | 5.1 (2.9 to 7.8) |
| 12 eggs | 9.2 (7.6 to 10.8) | 6.1 (3.5 to 9.4) |
| 15 eggs | 11.5 (9.4 to 13.5) | 7.7 (4.4 to 11.7) |
Lopez et al. (2014), 108 native-chicken raisers in Palawan, natural incubation. Hatch of eggs set was 76.44% and survival to weaning 66.89%. Multiply those through the 10.44-egg clutch the same survey measured and you get 5.34 weaned chicks, against the 5.68 it counted directly. Three separately measured figures reproducing the fourth is the strongest check any number on this site carries. The headline is the product: about ten eggs, about five and a half chicks. Roughly half. Every guide that quotes the hatch rate and stops there is one multiplication short.
Every figure in that table is Philippine and measured: Lopez, Lambio, Vega and De Guia (2014), 108 native-chicken raisers in Palawan, natural incubation under the hen. Hatch of eggs set came out at 76.44%, survival to weaning at 66.89%, and the clutches averaged 10.44 itlog. Nothing in the table assumes any of the eggs were fertile: the hatch figure is hatch of eggs SET, so whatever those flocks' tandang were doing is already inside it.
The number every other page stops one step short of
Ask how many chicks a broody hen gives you and you will be told 76%, which is true and is not the answer. A hatch rate is not a chick you can sell. Multiply it by the 66.89% that survive to weaning and a ten-egg clutch is about 5.1 sisiw walking around a month later against 7.6 that came out of a shell. Sayang, but that is the number to plan on. The check that makes this trustworthy is that the survey counted the outcome separately: 5.68 weaned per clutch, against the 5.34 its own three component figures multiply out to. Two independent routes to the same answer.
The three dates
Twenty-one days, turning stops on 18, and one candling window. Add these to the day you set, or use the box below.
| Day | What happens |
|---|---|
| Day 7 to 10 | Candle. Clear eggs come out; the flock is not fed by eggs that were never going to hatch. |
| Day 18 | Stop turning, raise the humidity, and leave the lid alone. |
| Day 21 | Hatch. Expect it to run late if the eggs were stored. |
Add these to your own set date, or use the box below and it will do it for you. Only one candling date is here: day 7 with the window open to day 10, which is what the MSD Veterinary Manual gives. The day-14 and day-18 checks every hobby page prints as a schedule could not be sourced to an extension service or a vet, so this page will not print a date for them.
What the machine should be holding
Two extension services, published side by side rather than averaged into a number neither of them wrote. They agree to within a tenth of a degree on forced air (Texas A&M, Mississippi State). The still-air row is the one to read twice, kasi the figure carries a measurement point: 38.9°C at the top of the egg, not at the floor of the machine. Those are two different machines and putting the thermometer in the wrong one cooks the clutch.
| Stage | Forced air, °C | Still air at egg top, °C | Humidity | Turning |
|---|---|---|---|---|
| Day 1 to day 18 | 37.5 to 37.8 | 38.9 | 55 to 60% | 5x a day, minimum |
| Day 19 to day 21 | 37.5 to 37.8 | 38.9 | 65 to 70% | Stop turning |
Texas A&M AgriLife Extension and Mississippi State Extension, read 13 August 2026, published side by side rather than averaged. The still-air figure is measured AT THE TOP OF THE EGG, not at the floor of the machine. The same reading taken in the wrong place is a different machine, and it is how a clutch gets cooked.
The week that costs you nothing, and the days after it
Texas A&M puts the storage penalty at 0.5 to 1.5% a day after seven days, and each day held adds about an hour to the time in the machine. A keeper collecting a clutch over two weeks before setting has already lost hatch bago pa mag-simula, and their hatch will run about half a day late. Both are computable and neither is on any competing Philippine page. The window Texas A&M asks for is 12.8 to 18.3°C at 70 to 80% humidity, which in most of this country is a refrigerator crisper rather than a shelf.
What the grid assumes
- The calendar is 21 days, turning stops on day 18, and the one candling date this tool projects is day 7 with the window running to day 10. Texas A&M AgriLife Extension for the calendar, the MSD Veterinary Manual for the candling window.
- The hatch rate is 76.44% give or take 13.48 points, measured under actual backyard natural incubation by Lopez et al. (2014) across 108 native-chicken raisers in Palawan. It is a Philippine figure for a Philippine bird, which is the whole reason this page exists.
- Survival from hatch to weaning is 66.89% give or take 20.2 points, from the same survey. Multiply the two and a clutch of 10.44 eggs comes out at about 5.34 weaned chicks, against the 5.68 the same survey counted directly. Three separately measured figures reproducing the fourth is the strongest check any coefficient on this site has.
- A broody hen turns her own eggs, so there is no turning instruction here and no humidity to set. What the machine rows below are for is comparison.
- The eggs were held 5 days, inside the week Texas A&M says costs nothing, so no storage penalty is applied to the hatch rate.
- Storage adds about an hour of incubation per day held, so this setting should run about 5 hours late. That is why a hatch sometimes starts on the evening of day 21 rather than the morning.
- 12 eggs set. Every chick figure on this page is that number times the rate above, and nothing on the page assumes any of them are fertile.
- The low and high figures are a best case and a worst case, not a plus-or-minus. They are built by multiplying the low ends together and the high ends together, so the spread is the widest outcome the published figures allow rather than a statistical interval. A keeper deciding whether ten eggs is enough needs the worst case, and it is the number every other page leaves out.
- Texas A&M states the storage penalty as "0.5 to 1.5% per day after 7 days of storage" without saying whether that is percentage points or a share of the rate. This tool reads it as percentage points, which is the conservative reading and the one hatchery guidance is usually written in: a 76.44% hatch held twelve days comes out at 71.44% here, against 72.7% on the other reading. The gap is small at realistic storage lengths and wide at three weeks, which is where the tool stops.
What it does not cover
- This is a calendar and an expectation, not a diagnosis. It cannot tell you whether an egg is fertile, whether the machine is holding its setting, or whether a hen is sitting tight.
- Fertility is not in the arithmetic anywhere. The Palawan hatchability figure is hatch of eggs SET, which already carries whatever fertility those flocks had. If your tandang is old, or there is one rooster to thirty hens, your own figure will sit below it and the tool cannot see that.
- Only one candling date is projected, day 7 with the window running to day 10, because that is the only candling day this site could source to an extension service or a veterinary manual. The day-14 and day-18 checks that appear on every hobby page are real practice and this tool will not print a date for them.
Why there is one candling date here and three everywhere else
Search for a candling schedule and you get day 7, day 14 and day 18, with what to look for at each. It is on essentially every hobby incubation page. A direct search for one extension service or veterinary manual giving all three days with per-day criteria found none. The MSD Veterinary Manual places candling at day 7 to 10, after the first embryonic mortality peak, and that is the only one this page will print a date for. Looking again at day 14 is real practice and worth doing. It is just not a coefficient anybody published, and projecting a calendar date off a number nobody published is what this site exists not to do.
The Philippine reality gap
One block of figures on this page is Philippine and measured: the Palawan survey of 108 native-chicken raisers, which is where the clutch size, the hatch rate and the survival to weaning come from. Everything about the machine is imported from Texas A&M and Mississippi State, written for a temperate room. Two things travel badly. The storage window assumes a room at 12.8 to 18.3 degrees, which is a refrigerator crisper in most of the Philippines and not a shelf; eggs held on a shelf at 30 degrees are ageing faster than the published decay describes. And a still-air machine in a house at 33 degrees cannot shed heat the way the same machine can in a house at 20, so the setting is a target rather than a promise. And the Palawan hatch this tool uses is broody-hen hatch of eggs set, not machine hatch: the one Philippine machine-hatch measurement for native eggs, Tadeo (2024) at the Abra State Institute of Sciences and Technology, runs far lower at 41 to 48 percent of eggs set, so a keeper running native eggs through an incubator in a hot house should expect to sit well below the figure here.
Where these numbers come from
- Tadeo DB (2024), Laying Performance and Hatchability Rate of True-To-Type Bolinao Native Chicken, Abra State Institute of Sciences and Technology, Diversitas Journal 9(1), incubator hatch of eggs set
diversitasjournal.
com. read on September 5, 2026Philippinebr - Texas A&M AgriLife Extension, Incubating and Hatching Eggs, POSC-PU-018 (04/22)
cdn-de.
agrilife. read on August 13, 2026importedorg - Mississippi State University Extension, Incubating Eggs
poultry.
msstate. read on August 13, 2026importededu - MSD Veterinary Manual, Laying and Reproduction in Backyard Poultry
merckvetmanual.
com read on August 13, 2026imported