To treat Chronic Respiratory Disease (CRD) in chickens, use appropriate antibiotics as prescribed by a veterinarian, and ensure optimal environmental conditions.
Chronic Respiratory Disease (CRD) is a common and serious condition in chickens caused by Mycoplasma gallisepticum. Left untreated, it can lead to severe respiratory distress, reduced egg production, and even death. This guide covers everything you need to know about identifying, treating, and preventing CRD in your flock.
What is CRD in Chickens?
CRD is a bacterial infection that primarily affects the respiratory system of chickens. It’s highly contagious and often triggered by stress factors like poor ventilation, overcrowding, or sudden weather changes. The disease progresses through three stages, each with distinct symptoms.
Stage 1 Symptoms
- Watery eyes (one eye may be affected first)
- Minimal eyelid swelling
- Slight nasal discharge
Stage 2 Symptoms
- Swollen orbital sinus (“donut” shape around eye)
- Pus-like eye discharge
- Sticky eyelids
- Open-mouth breathing
- Gurgling sounds
Stage 3 Symptoms
- Swollen cere (nose area)
- Red eyes
- Cheesy eye discharge
- Pasted eyelids
- Persistent gaping mouth
Effective Treatment Options
Treatment success depends on catching CRD early. Here are the most effective methods:
1. Antibiotic Treatments
| Antibiotic | Dosage | Duration | Notes |
|---|---|---|---|
| Doxycycline + Tylosine | As prescribed | 7 days | Water-soluble, treats whole flock |
| Lincomycin + Spectinomycin | As prescribed | 5-7 days | No egg withdrawal period |
| Chlortetracycline | As prescribed | 5-7 days | Safe for layers |
For individual birds, vets may prescribe enrofloxacin (Baytril) though it’s off-label use in chickens. Always consult a poultry veterinarian for proper diagnosis and treatment plans.
2. Supportive Care
- Isolate affected birds but keep with one companion
- Provide warm, draft-free environment
- Offer high-quality, palatable food
- Use saline nose drops to clear passages
- Apply vet-prescribed eye ointments
3. Stress Reduction
Since stress triggers CRD outbreaks, manage these factors:
- Improve coop ventilation
- Reduce overcrowding
- Maintain consistent temperatures
- Provide clean water and balanced feed
- Minimize handling during treatment
Prevention Strategies
1. Biosecurity Measures
- Quarantine new birds for 30 days
- Disinfect equipment regularly
- Limit visitor access to coop
- Use foot baths with disinfectant
2. Vaccination
While vaccines aren’t 100% effective, they can reduce severity. The Mycoplasma gallisepticum vaccine is typically given at hatch.
3. Nutritional Support
- Ensure adequate Vitamin A (deficiency mimics CRD symptoms)
- Add electrolytes during stress periods
- Consider probiotics for gut health
When to Cull Birds
Birds with advanced CRD (Stage 3) showing permanent damage should be humanely culled because:
- They won’t fully recover
- Serve as disease reservoirs
- Have reduced quality of life
- May spread infection to healthy flock members
Complicating Factors
CRD often occurs alongside other diseases, making treatment more challenging:
Common Co-Infections
- E. coli (most frequent complication)
- Infectious Bronchitis (IBV)
- Newcastle Disease
- Infectious Laryngotracheitis (ILT)
These combinations may require different treatment approaches. For example, oxytetracycline might be needed for certain bacterial co-infections.
Long-Term Management
Once CRD enters a flock, the bacteria remains present even after symptoms disappear. Manage carrier birds by:
- Maintaining excellent hygiene
- Reducing stress factors
- Monitoring for flare-ups
- Isolating and treating affected birds immediately
Remember that recovered birds can transmit CRD to their offspring through eggs. Consider replacing your breeding stock if CRD becomes a persistent problem.