🧪 Vet Guide 2025: Common Bacterial Diseases in Backyard Chickens—Prevention, Testing & Treatment 🐔

Backyard chickens bring joy, eggs, and companionship—but like all animals, they can get sick. Bacterial diseases are a major concern for backyard flocks and can lead to chronic illness, reduced productivity, or even death. In this 2025 flock health guide, Dr Duncan Houston breaks down the most common bacterial diseases in chickens, how to recognize signs of illness, prevent spread, and treat affected birds. 🧠🐓

📜 Chickens Are Food Animals

Even if you raise chickens as pets, they are classified as food animals. This means medications must follow strict withdrawal times for eggs and meat. Your vet will let you know how long to wait after treatment before consuming any products. 🥚🚫

In some cases, certain bacterial diseases may trigger a visit from state or federal veterinarians—and in rare cases, depopulation of the flock may be required. 🛑

🦠 Common Bacterial Diseases in Backyard Chickens

1. Chronic Respiratory Disease (CRD) – Mycoplasma gallisepticum

• 🫁 Symptoms: Coughing, nasal/eye discharge, sneezing, facial swelling
• 🧬 Carrier status: Birds remain carriers for life
• 💊 Treatment: Antibiotics reduce symptoms but do not cure
• 🛡️ Prevention: Source birds from Mycoplasma-free flocks

2. Infectious Coryza – Avibacterium paragallinarum

• 😮‍💨 Symptoms: Facial swelling, sneezing, discharge, reduced egg production
• 📆 Chronic: Surviving birds become lifelong carriers
• 💉 Prevention: Vaccine available, better for larger flocks

3. Fowl Cholera – Pasteurella multocida

• ⚠️ Symptoms: Sudden death, fever, joint swelling, yellow/green diarrhea
• 🧪 Treatment: Antibiotics for diagnosed cases; birds remain carriers
• 🛡️ Prevention: Vaccinate in endemic regions; excellent biosecurity is key

4. Infectious Synovitis – Mycoplasma synoviae

• 🦵 Symptoms: Lameness, joint swelling, green diarrhea
• 🧬 Carrier status: Birds remain infected for life
• 💊 Treatment: Antibiotics can reduce symptoms
• 🛡️ Prevention: Source from NPIP-certified flocks

5. Botulism – Clostridium botulinum

• ☠️ Symptoms: Rapid paralysis, “limberneck,” coma, sudden death
• 🧫 Cause: Ingesting spoiled feed, carcasses, or maggots
• 💉 Treatment: Antitoxin (expensive, limited access); supportive care
• 🛡️ Prevention: Strict sanitation and carcass removal

6. Pullorum Disease – Salmonella pullorum

• 🐣 Symptoms in chicks: Pasted vent, weakness, high mortality, respiratory signs
• 🧬 Status: Eradicated in U.S. flocks with NPIP certification
• 🛡️ Prevention: Only buy from certified disease-free sources

7. Fowl Typhoid – Salmonella gallinarum

• 📉 Symptoms: Sudden death, diarrhea, pale combs/wattles
• 🧬 Status: Also eradicated in the U.S. with NPIP controls

8. Necrotic Enteritis – Clostridium perfringens

• 💩 Symptoms: Rapid depression, bloody diarrhea, death within hours
• 💊 Treatment: Antibiotics, vitamins, supportive care
• 🛡️ Prevention: Good management, coccidiosis control

9. Salpingitis – E. coli (most common)

• 🥚 Symptoms: Decreased laying, bloating, walking difficulty
• 🔧 Treatment: Antibiotics or surgery; prognosis guarded

10. Bumblefoot – Secondary bacterial infection

• 🦶 Symptoms: Foot swelling, redness, abscesses
• 🔧 Treatment: Soaks, bandages, sometimes surgery
• 🛡️ Prevention: Proper footing, perching, drainage

11. Colibacillosis – E. coli

• 🦠 Symptoms: Diarrhea, fever, breathing issues, sudden death
• 💊 Treatment: Antibiotics, often poor prognosis in severe cases
• 🛡️ Prevention: Excellent sanitation and ventilation

💉 Testing & NPIP Certification

The National Poultry Improvement Plan (NPIP) helps keep flocks disease-free through rigorous testing and certification. Birds tested and certified through NPIP are guaranteed to be free of Salmonella pullorum/typhoid and avian influenza, and can also be certified for Mycoplasma species. ✅

Buying birds from NPIP-certified sources is the single most important step you can take to reduce the risk of serious bacterial disease. 🛡️

📦 Treatment, Carriers & Closed Flocks

Many treated birds will never fully eliminate the bacteria. These birds can still infect others—sometimes without showing any symptoms.

If your flock tests positive:

• 🐔 Keep your flock closed (no birds in or out)
• 🧼 Practice top-tier sanitation and quarantine protocols
• 📆 Consider depopulation for full eradication

📲 Ask A Vet: Backyard Flock Health Support

Worried about a sick chicken? Not sure if your flock is a carrier? Use the Ask A Vet app to consult with poultry vets like Dr Duncan Houston about biosecurity, vaccination, or treatment plans. 📱🐓

• 📸 Send photos of symptoms or injuries
• 🧪 Discuss testing, lab results, and withdrawal times
• 💬 Get care tips tailored to your local laws and flock size

Download the Ask A Vet app today and keep your flock healthy, happy, and hatching! 🐣💪

🏁 Final Thoughts: Health Starts with Hygiene

Chickens are hardy—but they rely on you for clean living conditions, smart sourcing, and swift treatment when illness strikes. A few key takeaways:

• 🧼 Prioritize cleanliness and fresh water
• 🐣 Buy only from NPIP-certified or tested flocks
• 📋 Work with a vet to manage or eliminate chronic infections

🐾 For expert help with treatment plans, biosecurity upgrades, or symptoms you’re unsure about, visit AskAVet.com or download the Ask A Vet app to speak with Dr Duncan Houston today. Because healthy chickens mean safe eggs, better meat, and a happier flock. 🐔💚