Understanding Poultry Post-Mortem Lesions: A Guide for Veterinarians

Poultry post-mortem examinations reveal critical clues about flock health, disease outbreaks, and management issues. For veterinarians, interpreting lesions accurately can guide diagnosis, treatment, and prevention strategies. This guide breaks down how to approach poultry post-mortem lesions with the precision and insight expected from a poultry vet.

Chicken liver with abnormal lesions, close-up view

Recognizing Common Lesions and Their Significance

Post-mortem lesions in poultry vary widely depending on the underlying cause. Some lesions point to infectious diseases, while others indicate nutritional deficiencies or environmental stress.

• Liver lesions: Enlarged, mottled, or necrotic livers often suggest bacterial infections such as Clostridium perfringens or viral diseases like infectious bursal disease. Fatty liver syndrome may show pale, friable livers.

• Air sac lesions: Cloudy or thickened air sacs with fibrin deposits typically indicate respiratory infections, such as infectious bronchitis or Escherichia coli infections.

• Intestinal lesions: Ulcers, hemorrhages, or thickened intestinal walls can result from coccidiosis or necrotic enteritis.

• Kidney lesions: Swollen or pale kidneys may point to nephropathies caused by infectious bronchitis virus or toxic insults.

• Skeletal lesions: Bone deformities or fractures can arise from nutritional imbalances or trauma.

  
  

Understanding the typical appearance of these lesions helps narrow down possible causes quickly.

Systematic Approach to Post-Mortem Examination

A structured method ensures no detail is overlooked during the examination.

1. External inspection

   Check the bird’s overall condition, feather quality, and any external wounds or swelling.

2. Body cavities

   Open the coelomic cavity carefully. Observe the color, size, and texture of organs such as liver, spleen, kidneys, heart, and lungs.

3. Respiratory system

   Examine trachea, air sacs, and lungs for signs of inflammation, exudate, or consolidation.

4. Digestive tract

   Inspect the crop, proventriculus, gizzard, intestines, and ceca for lesions, hemorrhages, or parasites.

5. Musculoskeletal system

   Look for bone abnormalities, muscle atrophy, or joint swelling.

6. Collect samples

   Take tissue samples for histopathology, microbiology, or molecular testing when needed.

   
   

Documenting findings with photos and notes supports accurate diagnosis and communication with producers.

Poultry necropsy table with opened bird showing internal organs, eye-level view

Interpreting Lesions in Context

Lesions alone do not provide the full picture. Consider the following factors:

• Age and production stage

Some diseases affect chicks differently than adult birds. For example, Marek’s disease lesions are more common in young birds.

• Flock history

Recent vaccination, feed changes, or environmental stressors influence lesion development.

• Clinical signs before death

Respiratory distress, diarrhea, or lameness reported by the farmer can guide lesion interpretation.

• Epidemiology

Disease outbreaks in the region or farm biosecurity status help prioritize differential diagnoses.

Combining lesion findings with this context improves diagnostic accuracy.

Examples of Lesions and Their Likely Causes

• Necrotic enteritis

Lesions include thickened intestinal walls with yellowish plaques. Caused by Clostridium perfringens, often linked to dietary changes or coccidiosis.

• Infectious bursal disease

Enlarged, hemorrhagic bursa of Fabricius with necrosis. Common in young broilers, leading to immunosuppression.

• Fowl cholera

Swollen joints, fibrinous exudate in air sacs, and liver necrosis. Caused by Pasteurella multocida infection.

• Coccidiosis

Bloody intestines with thickened mucosa and visible coccidia oocysts on microscopy.

• Fatty liver hemorrhagic syndrome

Pale, friable liver with hemorrhages, often in laying hens under stress or with high-energy diets.

These examples show how lesion patterns point to specific diseases.

Poultry liver affected by fatty liver hemorrhagic syndrome, high angle view

Tips for Accurate Lesion Interpretation

• Use good lighting and magnification to spot subtle changes.

• Compare lesions with healthy organ samples when possible.

• Take multiple samples from different organs for lab analysis.

• Keep detailed records of lesion descriptions and photos.

• Collaborate with diagnostic labs for confirmation.

• Stay updated on emerging poultry diseases and lesion presentations.

  
  

Veterinarians who master lesion interpretation can provide valuable advice to improve flock health and reduce losses.