Top Reasons Why Chickens Die (And How to Prevent It)

Chickens can die from various causes, including diseases, poor nutrition, environmental stress, predators, and inadequate housing or care.

Losing chickens can be heartbreaking, especially when the cause is unclear. Understanding why chickens die helps prevent future losses in your flock. From diseases to predators, we’ll cover all major threats and actionable prevention tips.

Causes of chicken mortality and health risks

1. Infectious Diseases

Diseases cause over 35% of chicken deaths according to veterinary studies. Many spread quickly through flocks if not addressed.

Marek’s Disease

This viral disease causes tumors and paralysis. It’s responsible for more chicken deaths than any other single cause. Vaccinate chicks at hatch to prevent it.

Respiratory Infections

Mycoplasma and other respiratory diseases spread through airborne particles. Symptoms include sneezing, nasal discharge, and swollen eyes. Keep coops well-ventilated but draft-free.

Internal Parasites

Worms and coccidia damage digestive systems. Regular deworming and proper parasite control prevents outbreaks.

Chickens under threat from predator attacks

2. Predator Attacks

Predators kill millions of backyard chickens annually. Common threats include:

Predator Signs Prevention
Raccoons Missing heads, torn vents Secure latches, electric fencing
Foxes Missing birds, scattered feathers Buried fencing, guard animals
Hawks Piles of feathers Overhead netting, hiding spots

For more predator protection tips, see our guide on stopping foxes from killing chickens.

3. Environmental Factors

Extreme Temperatures

Chickens can die from heat stress or hypothermia. Provide shade and ventilation in summer, insulation in winter. According to Penn State Extension, temperatures above 85°F become dangerous.

Toxic Substances

Common killers include:

  • Moldy feed (causes mycotoxicosis)
  • Pesticides and herbicides
  • Lead paint chips
  • Salt poisoning

4. Nutritional Deficiencies

Improper feed leads to:

  • Vitamin deficiencies (especially A, D, E)
  • Calcium depletion (soft-shelled eggs)
  • Protein deficiency (poor growth)

Always provide proper grit and supplements with balanced feed.

5. Reproductive Issues

Egg Binding

When hens can’t pass eggs, it’s often fatal. Obese hens and those with calcium deficiencies are most at risk.

Internal Laying

Eggs released into the body cavity cause infection. This condition requires veterinary intervention.

6. Sudden Death Syndrome

Some chickens die suddenly with no obvious cause. Possible reasons include:

  • Heart attacks (common in fast-growing breeds)
  • Aneurysms
  • Hidden infections

The PoultryDVM reports this affects about 2% of commercial broilers.

Prevention Checklist

  1. Vaccinate chicks against Marek’s disease
  2. Use predator-proof housing
  3. Provide clean water daily
  4. Feed high-quality ration appropriate for age
  5. Quarantine new birds for 30 days
  6. Clean coops regularly
  7. Monitor for early signs of illness

When to Seek Veterinary Help

Consult an avian vet if you notice:

  • Multiple sudden deaths
  • Birds showing neurological symptoms
  • Bloody diarrhea
  • Swollen joints or wattles

For more on keeping chickens healthy, read our article on preventing worms in chickens.