Hatching eggs is an exciting process, but sometimes, not all eggs hatch on time. The standard incubation period for chicken eggs is 21 days, but some may hatch later due to various factors. If you're experiencing late hatches, this guide will help you understand the causes and how to fix them to ensure a healthy hatch rate.
Common Causes of Late Hatching
1. Incorrect Temperature Settings
- Eggs incubated at temperatures slightly lower than the ideal range (99.5°F or 37.5°C for forced-air incubators and 101-102°F for still-air incubators) tend to develop more slowly.
- Temperature fluctuations during incubation can delay hatching.
✅ Fix: Ensure that the incubator maintains a stable and accurate temperature throughout the incubation period. Use a high-quality thermometer to double-check readings.
2. Humidity Issues
- Low humidity during incubation can cause the egg to lose moisture too quickly, resulting in weak or late hatches.
- High humidity can lead to excess moisture inside the egg, causing improper development.
✅ Fix: Maintain proper humidity levels:
- Days 1-18: 45-55%
- Days 19-21 (Lockdown phase): 65-75%
Use a hygrometer to monitor humidity inside the incubator.
3. Egg Quality and Storage Issues
- Fertile eggs stored for too long (over 10 days) before incubation can experience delayed or failed hatching.
- Eggs stored at incorrect temperatures (below 50°F or above 70°F) before incubation can lead to development issues.
✅ Fix:
- Store fertile eggs at 50-60°F with 75% humidity for no longer than 7 days before incubation.
- Turn stored eggs twice a day to keep the embryo from sticking to the shell.
4. Genetic Factors
- Some breeds naturally hatch later than others. Heritage breeds and larger eggs (like duck and turkey eggs) often hatch later than standard chicken breeds.
- Poor genetic selection may result in weak embryos that take longer to hatch.
✅ Fix: Choose high-quality fertile eggs from strong, healthy parent stock. If you notice late hatching trends in a specific line, consider improving breeding selection.
5. Improper Egg Turning
- If eggs aren’t turned regularly (at least 3-5 times daily) during the first 18 days, the embryo may develop abnormally, delaying hatching.
✅ Fix: If using a manual incubator, turn the eggs at least three times daily. Automatic turners should be checked for proper functioning.
6. Weak or Underdeveloped Embryos
- If the embryo develops too slowly due to nutritional deficiencies or improper incubation conditions, hatching will be delayed.
✅ Fix:
- Provide a balanced diet to breeding hens, rich in vitamins A, D, and E, as well as calcium and protein.
- Ensure fresh, fertile eggs for incubation.
7. Improper Ventilation
- A lack of oxygen due to poor incubator ventilation can lead to delayed or failed hatching.
✅ Fix: Ensure that the incubator has proper airflow and that vents are open during the last few days of incubation.
8. Early Egg Lockdown
- Stopping egg-turning too early or increasing humidity too soon can slow down development.
✅ Fix: Keep turning the eggs until day 18, and increase humidity only during the final three days (days 19-21).
How to Handle Late Hatching Eggs
- Wait Patiently – Some eggs naturally hatch a day or two late, especially if incubation conditions were slightly off.
- Candle the Eggs – Check for internal pipping (movement inside the shell) and blood vessels to see if the chick is still alive.
- Do Not Open the Incubator – Keep the incubator closed to maintain humidity levels. Opening it too often can cause shrink-wrapping, making it difficult for chicks to hatch.
- Assist Only If Necessary – If a chick has pipped but hasn't hatched for over 24 hours, you may consider assisting. However, this should be a last resort as premature intervention can harm the chick.
Conclusion
Late hatching is often caused by incorrect incubation conditions, egg quality, or genetics. By ensuring stable temperature, proper humidity, regular turning, and good egg storage, you can reduce delays and improve your hatch rate. If your eggs are hatching late, stay patient, monitor conditions, and only intervene when absolutely necessary.