(crop stasis, crop infection, "sour crop")

1.   What is the crop?

The crop is a part of the digestive system of most birds. It is a storage area for food before it enters the stomach. Young birds have a very large crop which contracts as the bird grows older. The crop wall is very thin in birds and is prone to tears, burns and injuries.


2. What causes crop problems?

Normally the crop empties shortly after the bird eats but sometimes a condition known as "crop stasis" occurs, in which there is a delay in the crop emptying. Delayed or reduced crop emptying can occur due to crop burns, overfilling or infections with parasites (eg trichomoniasis), fungi or bacteria. Kidney disease, heavy metal poisoning and viral disease (eg polyoma) can also be responsible. In handreared baby birds crop stasis may occur if the food they are fed is too cold. If the crop does not empty, the food inside then starts to decompose, leading to a condition often referred to as  “sour crop”. 


3. What are the clinical signs of a crop problem?

Clinical signs depend upon the severity of the disease. Signs range from “fluffing up” to decreased appetite, swollen crop, regurgitation and vomiting.  Depending on the cause of the problem, your bird may show other signs such as excessive thirst, abdominal swelling and changes in the appearance of the droppings (eg abnormal colour or consistency).


4. How is the crop problem diagnosed?

A sample is taken from the crop and examined under the microscope to look for fungi or other parasites.  Special staining of the crop sample is also necessary to determine the presence of harmful bacteria. In some cases, a culture and sensitivity laboratory test may also need to be performed to determine exactly which type of bacteria is present and the drug/s to which it is sensitive.

Blood tests or xrays may also be needed to detect the underlying cause eg heavy metal poisoning, kidney disease.


5. What is the treatment?

Treatment may involve antibiotics, anti-parasitic drugs, anti-fungal drugs, change in husbandry (eg temperature of food given to young birds) or just symptomatic treatment for the birds with suspected viral diseases. In severe cases your bird will need to stay in hospital for several days while it is stabilised and fluids and nutritional supplements administered.


6. What preventative measures are needed?

A good diet that includes pellets or crumbles and fresh foods; a clean cage environment with no exposure to toxic metals such as lead, zinc and copper; protection from wild birds; and protection from extremes of heat and cold. Annual health checks may find a crop problem before your bird becomes unwell.



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