Why didn't my eggs hatch? 12 causes and fixes

A failed hatch always leaves evidence. The key question is when the embryos died — that tells you why. Candle or carefully open the unhatched eggs and match what you find below.

Eggs candled clear — never developed (day 0–3)

1. Infertile eggs

Sign: egg glows evenly at day 7, opens with no blood at all. Fix: check your male ratio (1 rooster per 8–10 hens), rooster age and health. Fertility drops in extreme heat.

2. Eggs stored too long or badly

Sign: mostly clears from eggs older than 7–10 days. Fix: set eggs within 7 days of laying; store pointy-end down at 13–18 °C, not in the fridge and not in the sun.

3. Shipped/transported eggs shaken

Sign: clears plus detached air cells (air bubble moves when you tilt). Fix: rest transported eggs 24 h point-down before setting; expect 50% hatch from shipped eggs at best.

Blood ring — died in week 1

4. Temperature spike early on

Sign: many blood rings at day 7 candling. Fix: a few hours above 39.5 °C in week 1 kills embryos. Verify the incubator with a separate calibrated thermometer, and pre-run it 24 h before setting.

5. Bacteria (dirty or washed eggs)

Sign: blood rings plus bad smell, weeping or exploding eggs. Fix: set only clean, uncracked eggs; never wash off the protective bloom; wash hands before handling.

Died mid-development (day 8–17)

6. Temperature consistently wrong

Sign: embryos died at various middle stages. Too cool = slow development, late deaths; too warm = early deaths and rough hatches. Fix: hold 37.5 °C forced-air (38.5 °C still-air) ±0.3 °C.

7. Not enough turning

Sign: embryos stuck to the shell membrane, malpositioned. Fix: turn at least 3–5× daily until lockdown, or use an automatic turner.

8. Power cuts

Sign: deaths cluster around the outage date. Fix: a short cut (<4 h) with the lid kept closed is usually survivable — don't panic-open. For load-shedding areas: put the incubator on an IPS/UPS line.

Fully formed but dead in shell (day 18+)

9. Humidity too low in lockdown

Sign: chicks pipped the membrane but dried out and stuck ("shrink-wrapped"). Fix: raise lockdown humidity to 65–70%+ and stop opening the incubator during hatch — every peek dumps the humidity.

10. Humidity too high the whole time

Sign: fully formed, wet, mushy chicks that never pipped; small air cell. Fix: run 50–55% humidity days 1–18 (dry-hatch even lower in humid climates like Bangladesh); track the air cell size at candling.

11. Poor ventilation

Sign: full-term deaths with no other explanation, especially in packed incubators. Fix: embryos breathe through the shell — open the incubator's vent holes progressively in the final week; never seal them for humidity.

12. Breeder nutrition

Sign: weak chicks, crooked toes, deaths at every stage across multiple batches with good settings. Fix: feed parent stock a proper breeder ration (vitamins A, D, E, B12, riboflavin) — not just scratch grain — for 3–4 weeks before collecting hatching eggs.

Post-mortem checklist for the next batch

1. Count: how many clear, blood ring, mid-dead, full-term dead, hatched. The biggest group is your diagnosis.
2. Fix ONE thing at a time, or you won't know what worked.
3. Get the schedule right with the incubation calculator and stick candling dates on the incubator.
4. Log every batch: set date, settings, results. Three logged batches beat ten guessed ones.

Related: Egg candling guide with pictures · Incubation calculator