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Other Names: Air Sac Cold, Air Sac Infection, Air Sac Syndrome, Air Sac Disease

Airsacculitis is a lower respiratory-associated disease in chickens, and is defined as inflammation of one or more of the air sacs. Air sacs serve as an integral part of a chicken's respiratory system. Chickens have nine air sacs, which are thin-walled bubble-like pockets that work as a system to circulate oxygen throughout their bodies. There are four paired air sacs (cervical, cranial and caudal thoracic, and abdominal) and one unpaired air sac (clavicular).

When a chicken's air sacs become inflammed, it causes them to thicken and accumulate purulent, or caseous material within the air sac cavity. This is usually caused by a bacterial or fungal infection, and less commonly a virus. Some of the most common pathogens isolated from chickens with airsacculitis include Escherichia coli and Mycoplasma gallisepticum.
Airsacculitis causes in chickens
Specific diseases associated with onset of airsacculitis include:
  • Avian chlamydiosis: Avian chlamydiosis (AC) is a zoonotic respiratory disease of chickens caused by gram-negative bacteria from the Chlamydia genus. The genus consists of 11 different species from the Chlamydiaceae family. Chickens are predominately affected by C. psittaci, C. gallinacea and C. suis. Clinical signs vary depending on the virulence of the chlamydial strain and immune status of the bird. The most frequently reported signs in chickens include nasal and ocular discharges, difficulty breathing, diarrhea, weight loss, reduced egg production in hens, hyperthermia, lethargy and dullness.
  • Newcastle disease (ND): Newcastle disease is a highly contagious viral infection of domestic and wild birds worldwide. Since wild birds can sometimes carry the virus, outbreaks can occur anywhere poultry is raised. ND is caused by Newcastle disease virus (NDV), also known as Avian paramyxovirus-1 (APMV-1). The severity of ND varies widely and is dependent on factors such as: the strain of the virus, the age of the chicken (young chicks are more susceptible), concurrent infection with other organisms, stress and immune status. Some virus strains attack the nervous system, others the respiratory, or digestive systems.
  • Chronic respiratory disease (CRD): Chronic respiratory disease (CRD), also known collectively as mycoplasma gallisepticum (MG) infection, is considered to be one of the major pathogens that cause respiratory disease in poultry. It tends to develop slowly in flocks and associated with progressive and chronic respiratory signs. Chickens with chronic respiratory disease often show clinical signs associated with the respiratory system, which include tracheitis, sinusitis, airsacculitis and conjunctivitis.
  • Aspergillosis: Aspergillosis is a common fungal disease of chickens caused by infection with the genus Aspergillus, which consists of approximately 600 different species. A. fumigatus is the most common species isolated from infected chickens. Aspergillosis manifests as two different forms in chickens. Acute aspergillosis, also referred to as brooder pneumonia is characterized by severe outbreaks in newly hatched chicks and is associated with high morbidity and high mortality rates. Chronic aspergillosis usually occurs in adult birds living in poorly ventilated, dusty or moldy environments.
  • Ornithobacteriosis: Ornithobacteriosis is an emerging, acute and highly contagious disease of chickens, caused by Ornithobacterium rhinotracheale bacterium. It causes respiratory disease in chickens and turkeys worldwide. O. rhinotracheale is a rod-shaped, gram-negative, bacterium with several serotypes. The disease often presents as pneumonia or airsacculitis in affected flocks.

Clinical Signs

Difficulty breathing
Open-mouthed breathing
Low exercise tolerance


  • History
  • Clinical signs
  • Physical exam
  • Radiography
  • Auscultation of lungs and air sacs
  • Histopathy
  • Necropsy
  • Positive bacterial culture

Reported Cases

  • Case 1: Airsacculitis in a Pheasants Outbreaks of respiratory disease were investigated in reared pheasants aged approximately 18 to 32 weeks, released into the semi-wild on four shooting estates in southern England. The clinical signs in the affected birds included swelling of the face and eyes, loss of condition, gasping respirations and coughing. The gross pathology findings included sinusitis, airsacculitis, pleural oedema and lung lesions. The histopathological findings in the affected lungs were characterized by a granulomatous pneumonia. Ornithobacterium rhinotracheale (ORT) was isolated from respiratory tract tissues, and 16S rRNA gene sequencing on three isolates revealed two distinct genotypes, one previously associated with some electrophoretic type (ET) 1 strains and the other a novel genotype that clustered among sequences previously associated with ET 3, ET 4, ET 5 and ET 6 isolates. In each case, ORT was identified as part of a complex of other respiratory agents including avian paramyxovirus type 2, avian coronavirus, Mycoplasma gallisepticum, Mycoplasma synoviae and other Mycoplasma species, Escherichia coli, Pasteurella multocida, other Pasteurellaceae and Syngamus trachea, suggesting synergism with other agents. Exposure to other intercurrent factors, including adverse weather conditions and internal parasitism, may also have exacerbated the severity of disease. Ref


Supportive careIsolate the bird from the flock and place in a safe, comfortable, warm location (your own chicken "intensive care unit") with easy access to water and food. Limit stress. Call your veterinarian.
Identification of the cause and corresponding treatment



  • Design for adequate ventilation and good air flow in chicken coop
  • Minimize stress
  • Prevent birds from getting chilled during cold weather
  • Prevent exposure to dust
  • Don't use dusty or very fine bedding as litter for birds

Scientific References

Age Range

Risk Factors

  • Keeping chickens in poorly ventilated areas with little to no air circulation
  • Exposure to dusty environment or use of dusty or ultra-fine bedding litter
  • Sweeping out or cleaning coop while chickens are still inside
  • Stress