During the cold season, the incidence of respiratory diseases in chickens often increases significantly, causing considerable economic losses for poultry farmers. What are the underlying causes, and what measures should be taken to minimize this condition?
Whenever cold weather, prolonged rain, and high humidity occur, chickens commonly develop wheezing, respiratory rales, dyspnea, and in some flocks, scattered mortality. Treatment may be prolonged with frequent relapses. Why do cold and humid conditions predispose chickens to respiratory tract infections and pneumonia?
I. LOW TEMPERATURES SUPPRESS THE IMMUNE SYSTEM
When ambient temperatures decline – particularly at night and early morning – chickens must utilize substantial metabolic energy to maintain thermoregulation.
Consequences include:
– Decreased immune competence
– Lowered disease resistance
– Increased susceptibility to respiratory pathogens
Under these stress conditions, diseases such as Chronic Respiratory Disease (CRD), secondary E. coli infection (colibacillosis), and Infectious Bronchitis (IB) can easily emerge, resulting in respiratory rales, gasping, and pulmonary inflammation.
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II. HIGH HUMIDITY – A MAJOR THREAT TO THE RESPIRATORY TRACT
Prolonged dampness leads to:
– Wet poultry houses
– Moist litter
– Poor air circulation with ammonia accumulation
Such environments promote the growth of bacteria, fungi, and other microorganisms.
Inhalation of contaminated air damages the nasal and tracheal mucosa → facilitates bacterial invasion → resulting in respiratory tract inflammation and pneumonia.
III. IMPROPER HOUSE SEALING – A COMMON MANAGEMENT ERROR
During cold weather, many farmers tend to:
– Completely cover the house with tarpaulins
– Close all doors and ventilation openings, eliminating proper airflow
This leads to: Accumulation of toxic gases (especially ammonia) from manure, Reduced oxygen levels, Increased humidity
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Prolonged exposure to toxic gases predisposes chickens to respiratory disorders such as wheezing and open-mouth breathing. Conversely, improper sealing may also cause drafts—particularly at night—where cold air directly impacts the flock, further increasing the risk of respiratory disease.
In reality, many flocks may already harbor latent pathogens but remain asymptomatic due to adequate immune status.
When exposed to unfavorable conditions such as cold stress, environmental stressors, and reduced immunity, clinical disease can be triggered.
Therefore, during cold weather, farmers should closely monitor their flocks and promptly detect abnormal signs for early intervention.
IV. CLINICAL SIGNS REQUIRING IMMEDIATE ATTENTION
– Mild wheezing, more noticeable at night
– Sneezing and nasal discharge
– Audible abnormal respiratory sounds
– Huddling together, ruffled feathers
– Significant reduction in feed intake
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Prompt diagnosis and appropriate therapeutic intervention are essential to improve treatment outcomes. In addition, proper brooding temperature management, maintaining dry litter, ensuring adequate ventilation, and enhancing immune status are key preventive strategies. Supplementation with products such as VITA C 20%, GLUCAN C, or combined administration of MIXOIL ORAL (spray and drinking water) can support immune function and maintain respiratory health.
Prevention remains the most effective approach. Careful flock observation, early recognition of symptoms, and proper environmental management are fundamental to maintaining flock health throughout the cold season.