Body Condition Scoring in Birds


Body condition scoring (BCS) is a useful tool for assessment of a patient’s general health status and evaluation of a patient’s food supply. The BCS system described below is based on scores between 1 and 5, with 1 being emaciated and 5 being obese for the “generic” bird (Fig 1).

Profound emaciation in a cockatoo with neuropathic ganglioneuritis

Figure 1. This emaciated bird (body condition score 1) is bony with almost no muscle overlying the sternum. Photograph provided courtesy of Dr. Isabelle Langlois. Click image to enlarge.

Currently there is no universally agreed upon BCS system for the avian patient due to the high degree of species variability. Individual variability is also seen within a species, and can be due to the level of activity (i.e. wing trimmed versus active flier), “life style” (i.e. free-ranging versus captive), and the season of the year (particularly in migratory species).


Assessing body condition score in adult birds

Always evaluate body condition in conjunction with body weight. Weigh all birds in grams as part of the physical examination.

To evaluate body condition:

  • Palpate the breast muscles immediately alongside the ventral ridge of the keel bone or carina. Note the convexity or concavity of the pectoral muscle mass contour (Fig 2)
  • Note the degree of prominence of the keel (Fig 2)

    Transverse sections of the sternum and pectoral muscle mass, body condition score

    Figure 2. Transverse sections of the sternum and pectoral muscle mass in the avian patient displaying body condition score (BCS) where (a) is the keel or carina of the sternum, (b) is pectoral musculature, and (c) is the sternum. Emaciation = little muscle, no fat, concave contour (BCS 1). Good condition = convex contour, little subcutaneous fat (BCS 3). Obese: contour extends beyond keel, subcutaneous fat deposits. Click image to enlarge.

  • Look for subcutaneous fat deposits over the sternum, sides, coelom, flanks, thighs, and neck. Wetting feathers with alcohol can improve visualization of yellow subcutaneous fat deposits (Fig 3)

    Subcutaneous fat deposits in a cockatiel.

    Figure 3. Subcutaneous fat deposits in a cockatiel. Photograph provided by Dr. Ed Ramsay. Click image to enlarge.

Body condition scores were originally created to try to quantify the degree of pectoral muscle mass lost in ill birds. These systems can be less accurate in identifying or quantifying obesity, however as body condition increases body weight and fat stores increase.

  • The thin bird (BCS 1 to 2) is bony with little muscle over the sternum (Fig 1). The keel bone will display a prominent “V” shape.
  • The bird in ideal body condition (BCS 3) has a good overall appearance, with a pectoral muscle contour appropriate for the species.
  • An overweight to obese bird with a BCS of 4 to 5 has a plump breast with variable amounts of subcutaneous fat and coelomic distension. The contour of the chest displays a broad “U” shape.

Overweight birds often deposit fat within subcutaneous tissues, particularly over the coelom and lateral flanks. Subcutaneous fat depots in the inguinal space can create a broad-based stance, while fat deposits underneath the beak can create a “double chin”. Fat deposits along either side of the keel can also create a part in feathers overlying the sternum, although the presence of “cleavage” does not necessarily mean the bird is overweight (Fig. 4). Morbidly obese patients, particularly budgerigar budgerigars and Amazon parrots, can also possess lipomas.

Part in feathers over the sternum

Figure 4. Fat deposits along either side of the keel may create a part in feathers over the sternum. Note: The presence of “cleavage” does not necessarily mean the bird is overweight and palpation is required. Photograph provided by Dr. Gwen Flinchum. Click image to enlarge.

Body condition score in juvenile birds

In pediatric patients, body condition cannot be assessed by palpation of the pectoral muscle mass, which is small, soft, and flabby. Instead, evaluate the amount of soft tissue and fat over bony areas like the pelvis and toes.




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To cite this page:

Pollock C. Body condition scoring in birds. October 6, 2012. LafeberVet Web site. Available at