Why Do Chicks Die in the Shell? Causes & Prevention
Hatching chicks successfully is both an art and a science. Whether you are a backyard poultry farmer or run a large-scale hatchery, dealing with unhatched eggs containing fully formed but dead chicks can be frustrating. Understanding the reasons behind chick mortality inside the shell can help you take preventive measures and improve hatch rates.
In this detailed guide, we’ll discuss the common causes of chick mortality inside the shell and the best prevention techniques to ensure healthier and stronger hatchlings.
Understanding Chick Mortality in the Shell
When an embryo develops normally but fails to hatch, it is classified as late embryonic death or pipped but not hatched. This is a common issue in poultry incubation, and the underlying causes vary, including nutritional deficiencies, improper incubation conditions, bacterial infections, and genetic problems.
Key Signs of Late Embryonic Death:
✅ Fully formed chick inside the shell
✅ Dead chick with the head under the right wing (normal hatching position)
✅ Presence of a blood ring inside the shell
✅ No external pip marks
By identifying these signs and addressing the root causes, hatchery owners can minimize losses and boost hatch rates significantly.
Common Causes of Chicks Dying in the Shell
1. Incorrect Incubation Temperature & Humidity
One of the primary causes of chick death in the shell is an unstable incubation environment. Eggs require a consistent temperature of 99.5°F (37.5°C) and a relative humidity of 50-55% during incubation. Any fluctuation in these conditions can cause developmental abnormalities and weak chicks.
🔴 How It Affects Hatchability:
- High temperature → Dehydration and weak embryos
- Low temperature → Delayed development and late hatching
- Low humidity → Difficulty in breaking the shell
- High humidity → Poor air cell development and drowning of the chick
✅ Prevention Tips:
✔️ Use a high-quality incubator with an accurate thermostat and hygrometer
✔️ Monitor and maintain temperature and humidity levels regularly
✔️ Increase humidity to 65-75% during the last 3 days (lockdown period)
2. Poor Egg Quality & Storage Issues
The quality of eggs used for incubation plays a critical role in hatchability. Fertile eggs that are too old, cracked, dirty, or misshapen have a higher chance of embryo mortality.
🔴 How It Affects Hatchability:
- Old eggs (stored over 10 days) → Weak embryos that fail to hatch
- Cracked or thin-shelled eggs → Bacterial contamination
- Dirty eggs → Increased risk of infections
- Improper storage → Embryo cell damage
✅ Prevention Tips:
✔️ Use fresh, clean, and properly sized fertile eggs for incubation
✔️ Store eggs at 55-65°F (13-18°C) with 75% humidity before incubation
✔️ Do not wash eggs, as it removes the protective cuticle
3. Inadequate Ventilation & Oxygen Supply
Developing embryos breathe through the eggshell, absorbing oxygen and expelling carbon dioxide. If the incubator does not provide proper airflow, chicks may suffocate inside the shell before hatching.
🔴 How It Affects Hatchability:
- Poor ventilation → Carbon dioxide buildup → Embryo suffocation
- Lack of fresh oxygen → Weak chicks that fail to hatch
✅ Prevention Tips:
✔️ Ensure the incubator has proper ventilation holes
✔️ Avoid overcrowding eggs in the incubator
✔️ Keep the incubator in a well-ventilated room
4. Nutritional Deficiencies in Breeder Hens
Healthy chicks come from healthy parent stock. If the breeder hens lack essential vitamins, minerals, and proteins, their eggs may have weakened embryos that cannot survive the incubation period.
🔴 How It Affects Hatchability:
- Vitamin A deficiency → Poor embryonic growth
- Vitamin D3 deficiency → Soft or malformed bones
- Vitamin E & Selenium deficiency → Weak muscles and failure to hatch
- Calcium & Manganese deficiency → Deformed legs and beak
✅ Prevention Tips:
✔️ Feed breeder hens a balanced diet rich in vitamins and minerals
✔️ Include calcium, phosphorus, and trace minerals in their feed
✔️ Supplement with probiotics and antioxidants for stronger embryos
5. Bacterial & Fungal Infections
Pathogens like E. coli, Salmonella, and Aspergillus (fungus) can infect eggs and cause embryo mortality before hatching.
🔴 How It Affects Hatchability:
- Bacteria penetrate the eggshell → Infected embryo → Early or late death
- Fungal contamination → Embryo dies due to respiratory infection
✅ Prevention Tips:
✔️ Maintain strict hygiene in the incubator and surrounding area
✔️ Disinfect incubators and equipment after every hatch
✔️ Use only clean and disinfected eggs for incubation
How to Improve Hatchability & Prevent Chick Mortality in the Shell
✅ Follow These Best Practices for High Hatch Rates:
1️⃣ Use High-Quality Fertile Eggs – Ensure eggs are fresh, clean, and stored properly before incubation.
2️⃣ Maintain Optimal Incubation Conditions – Keep temperature, humidity, and ventilation at correct levels.
3️⃣ Rotate Eggs Regularly – Turn eggs at least 3-5 times daily to prevent embryos from sticking to the shell.
4️⃣ Increase Humidity Before Hatching – Raise humidity to 65-75% in the last 3 days (lockdown period).
5️⃣ Candle Eggs to Check Development – Monitor egg fertility at day 7, 14, and 18 to remove non-viable eggs.
6️⃣ Keep the Incubator Clean – Disinfect the incubator before and after every batch of eggs.
7️⃣ Avoid Frequent Opening of the Incubator – Minimize disturbance during lockdown (last 3 days).
8️⃣ Ensure Good Ventilation – Provide enough oxygen for developing embryos.
Final Thoughts
Chicks dying inside the shell is a frustrating problem, but with proper management and prevention techniques, you can significantly improve hatch rates. Maintaining the right incubation conditions, selecting high-quality eggs, ensuring proper nutrition for breeder hens, and keeping the incubator clean are key to successful hatching.
By following these best practices, poultry farmers can reduce embryo mortality and achieve healthier chicks for a thriving poultry business.
👉 Have you experienced issues with chick mortality inside the shell? Share your experiences and questions in the comments below!