Why Your Eggs Didn't Hatch: Reading a Failed Batch
TL;DR: A failed hatch is evidence, not just a loss. Open the unhatched eggs and note when development stopped: no development at all means infertile or badly stored; a blood ring means early death; fully formed but never pipped points at humidity too high across incubation; pipped then died points at humidity too low at lockdown or the lid being opened. Early hatch means too warm, late hatch means too cool. Write it down — that record is what makes the next batch better.
This is the least pleasant job in incubation and the most useful one. Almost nobody does it, which is why the same people have the same bad hatches repeatedly.
Do the Post-Mortem
Wait until the hatch is genuinely over — a couple of days past day 21, since late hatches happen — then open the unhatched eggs one at a time, away from where you keep birds, and look.
Warning: an egg that has been rotting can be under pressure and smells appalling. Open them outdoors, in a bag, and wash your hands afterwards.
What you are recording for each egg: was there development, and if so, how far did it get?
The Diagnostic Table
| What you find | What it means | Most likely cause |
|---|---|---|
| Clear, like a fresh egg | Infertile — never started | No rooster, poor fertility, or eggs stored too long/badly |
| Blood ring, or tiny embryo with collapsed vessels | Fertile, died in the first days | Storage problems, rough handling, temperature spike early, contamination |
| Embryo dead around mid-term | Died in development | Temperature swings, poor turning, contamination |
| Fully formed, dead in shell, not pipped, appears wet | Reached term but never got out | Humidity too high — air cell too small; also poor turning or late temperature problems |
| Pipped then died, membrane dry and tough | Started hatching and got stuck | Humidity too low at lockdown, or the incubator was opened |
| Hatched early (day 19–20), chicks weak or small | Development accelerated | Temperature too high |
| Hatched late (day 22+), drawn out | Development slowed | Temperature too low |
| Hatch spread over several days | Uneven conditions | Temperature swinging, hot and cool spots, or eggs set at different times |
| Bad smell, dark contents | Bacterial contamination | Dirty eggs, washed eggs, cracked shells, dirty incubator |
The Big Four Causes
1. Fertility. No rooster, an old or unfit rooster, too many hens per rooster, or a rooster that cannot mate properly. Nothing in the incubator can fix an infertile egg. Candle at day 7 — clear eggs at day 7 were never going to hatch and can be removed. See candling eggs.
2. The eggs before they went in. How eggs were collected, stored and handled matters as much as the incubator. Eggs stored too long, stored too warm, washed, or visibly dirty all reduce hatch — see how to store hatching eggs.
3. Temperature. Running hot, running cold, or swinging. The hatch date itself is your best evidence: early means hot, late means cool. See incubator temperature — and verify your thermometer, since the most common cause is an incubator reading one thing while the eggs experience another.
4. Humidity. The two clear signatures are in the table above: fully formed but never pipped (too wet), pipped then stuck (too dry at lockdown). See incubator humidity and lockdown at day 18.
The Two Failures You Cause Yourself
Opening the incubator during lockdown. Humidity crashes, membranes dry, pipped chicks get stuck. If your unhatched eggs are pipped-then-dead and you opened the lid to look, you already know the cause.
Missed turning. Nothing looks wrong at the time. It shows up as embryos adhered to the shell membrane and as badly positioned chicks at term. See egg turning.
Contamination: The Cause People Skip
A warm, humid box is an excellent bacterial incubator too.
- Do not set visibly dirty eggs. Bacteria travel through the porous shell.
- Do not wash hatching eggs. Washing removes the natural cuticle and can drive contamination inward. Wipe very lightly if you must, and prefer clean eggs from clean nests.
- Do not set cracked eggs.
- Clean and disinfect the incubator between batches. Hatch debris left in the machine is the next batch’s problem.
- Wash your hands before handling eggs.
The clue is the smell and the dark, liquid contents of an opened egg. If several eggs are like that, contamination is your problem and no setting change will fix it.
What a Normal Hatch Rate Looks Like
Before concluding you failed, check the expectation. Not every fertile egg hatches, even in commercial hatcheries with far better equipment. Our what hatch rate should you expect guide covers what is realistic for backyard conditions and how to calculate it honestly — fertility and hatchability are two different numbers, and mixing them up is how keepers misdiagnose their own results.
Write It Down
For each batch: source of eggs, storage time, set date, temperature and humidity readings you actually observed, turning method, candling results at day 7 and 14, hatch date, number hatched, and what you found in the unhatched eggs.
Three batches of that log will tell you more about your machine, your room and your birds than any guide, this one included.
The Honest Limits Here
The associations between hatch-failure patterns and their causes described here are standard incubation troubleshooting, consistent with our main incubation guide. They are associations, not certainties — several causes can produce similar findings, and a single batch is a small sample. Look for the pattern across the whole batch and across batches rather than diagnosing from one egg. Where your incubator’s manual gives model-specific guidance, follow it.
Related: candling eggs, incubator temperature, incubator humidity, how to store hatching eggs.
Frequently Asked Questions
Why did none of my eggs hatch?
The most common causes are infertile eggs, eggs stored too long or badly before setting, incubator temperature problems, and humidity problems. Opening the eggs afterwards and noting when development stopped tells you which.
How do I tell an infertile egg from an early death?
An infertile egg looks essentially like a fresh egg inside, with no blood vessels ever formed. An early death shows a blood ring or a small embryo with vessels that started and stopped. Candling at day 7 shows the difference too.
What is a blood ring?
A ring of blood visible when candling or when the egg is opened, formed when an embryo started developing and then died and the blood vessels collapsed into a ring. It means fertile but died early.
What does it mean if chicks were fully formed but never pipped?
Fully developed chicks dead in the shell without pipping is commonly associated with humidity being too high through incubation, so the air cell stayed too small. It can also follow poor turning or a temperature problem late on.
What if they pipped and then died?
That pattern most often points to humidity being too low at lockdown or the incubator being opened during it, leaving a dried membrane the chick could not cut through.
Why did my eggs hatch early or late?
Early hatching usually means the incubator ran warm; late hatching usually means it ran cool. Both are temperature signals worth acting on.
Is a rooster needed for eggs to hatch?
Yes. Hens lay without a rooster but those eggs are infertile and cannot hatch. A rooster is required only for fertile eggs.