Chickens may die due to various reasons, including disease, poor nutrition, predators, environmental stress, or inadequate care; consult a vet for specific issues.
Losing chickens unexpectedly can be heartbreaking and frustrating. Whether you’re missing one bird or facing a sudden mass mortality event, identifying the cause is critical to protect your remaining flock. Here’s what every poultry keeper needs to know.
1. Parasitic Infections (Coccidiosis)
Coccidiosis is the #1 killer of young chickens worldwide. This parasitic disease attacks the intestinal tract, causing:
- Bloody diarrhea
- Lethargy
- Pale combs
- Sudden death in severe cases
Treatment: Use Corid (amprolium) at 2 tsp per gallon for 5-7 days. Remove all untreated water sources during treatment.
Prevention Tips
- Keep bedding dry (change pine shavings weekly)
- Provide 4 sq ft per bird to reduce contamination
- Use medicated starter feed for chicks
2. Predator Attacks
Predators don’t always leave obvious signs. Common culprits include:
| Predator | Tell-Tale Signs |
|---|---|
| Raccoons | Missing heads, entrails left behind |
| Foxes | Birds carried away, few feathers |
| Weasels | Neck bites, multiple dead birds |
Solution: Install predator-proof fencing with buried hardware cloth and automatic coop doors.
3. Toxic Exposure
Chickens can die quickly from:
- Moldy feed (produces deadly aflatoxins)
- Pesticides/rodenticides
- Treated lumber in coops
- Certain plants like nightshade
Case Study: A Kentucky flock lost 12 birds after eating moldy corn. Necropsy revealed liver failure from aflatoxin poisoning.
4. Respiratory Diseases
Mycoplasma gallisepticum (chronic respiratory disease) causes:
- Gurgling breathing
- Swollen sinuses
- 40% mortality if untreated
According to poultry health experts, early antibiotic treatment with Tylan 50 can save affected birds.
5. Heat Stress
Chickens overheat at 85°F+ temperatures. Warning signs:
- Panting with open beaks
- Wings held away from body
- Sudden death in severe cases
Emergency cooling: Add electrolytes to water and mist coop with cool water.
6. Egg Binding
Common in high-production hens, symptoms include:
- Straining with no egg production
- Lethargy
- Swollen abdomen
Solution: Warm epsom salt baths and calcium supplements. Read more about egg abnormalities that may indicate health issues.
7. Fowl Cholera
This bacterial disease spreads rapidly with:
- Greenish diarrhea
- Swollen joints
- 50-75% mortality rate
Prevention: Vaccinate flocks in endemic areas and quarantine new birds for 30 days.
8. Vent Gleet
A fungal infection showing:
- White discharge from vent
- Foul odor
- Feather loss around vent
Treatment: Apple cider vinegar in water (1 tbsp per gallon) and antifungal creams.
9. Internal Laying
When eggs develop inside the body cavity instead of the oviduct, causing:
- Abdominal swelling
- Difficulty walking
- Sudden death from peritonitis
10. Marek’s Disease
This herpesvirus causes:
- Paralysis of legs/wings
- Gray irises in eyes
- 100% mortality in unvaccinated birds
Vaccinate day-old chicks – the only effective prevention.
11. Cannibalism
Birds may peck others to death due to:
- Overcrowding
- Bright lighting
- Nutritional deficiencies
Solution: Use anti-pecking sprays and provide enrichment.
12. Old Age
Even with perfect care, hens typically live 5-8 years. Signs of aging include:
- Decreased egg production
- Weight loss
- Difficulty perching
For persistent unexplained deaths, submit a fresh carcass to your state veterinary diagnostic lab. As noted in poultry forums, sometimes multiple factors contribute to mortality events.