Veterinary advice should be sought from your local veterinarian before applying any treatment or vaccine. Not sure who to use? Look up veterinarians who specialize in poultry using our directory listing. Find me a Vet

Breast Blister

Other Names: Keel Lesions, Keel Cysts, Sternal Bursitis

Breast blister (BB), also referred to as keel cyst, is the inflammation of the sternal bursa along the keel bone of the chicken, in the breast area. It is usually seen in chickens who are sick or injured and spending most of their time lying down on their breast bone. It is also seen in commercial broiler chickens who are unable to stand due to their excessive weight, and therefore immobile. The severity varies from mild to severe, and can include feather loss and inflammation to extensive, fluid-filled blisters.

Clinical Signs

Reddening and irritation in breast bone area


  • History
  • Clinical signs
  • Physical exam
  • Culture


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.
Wound careClean the affected area and flush with antiseptic.
Apply wound dressing and keep clean.
Isolate from flock and place in a recovery first aid area until fully healed.
If already in recovery for an illness or injuryUse soft materials for birds to rest on---such as foam egg crate mattress topper.
AntibioticsMay be indicated to prevent secondary bacterial infections if there is skin breakage.



  • Invest or make a chicken therapy chair for injured or paralyzed birds, to prevent them from resting on their breast bone for an extensive amount of time.
  • Use soft materials for birds to rest on---such as foam egg crate mattress topper.
  • Replace any damp bedding materials quickly so birds aren't resting on them for long periods of time.

Scientific References

Risk Factors

  • Sick, injured, and/or paralyzed birds who spend most of the time lying down on their sternum or breast bone.
  • Birds kept on hard or wire floor
  • Use of coarse or wet bedding
  • Birds with poor feather cover