Yeast Infection in Birds

Jessica Hockaday, DVM
By Jessica Hockaday, DVM on Mar. 14, 2024
green bird up close

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In This Article


What Is a Yeast Infection in Birds?

Yeast is an opportunistic organism, meaning it can cause disease and other problems in pet birds and poultry when their immune systems are under stress.

The most common yeast in birds, Candida albicans, is found in the bird’s digestive tract. This type of yeast is naturally found in the environment, including soil, water, plants, and decaying organic debris. When the immunity of a bird is low, the yeast can cause a secondary infection of Candidiasis.

Many species of birds have a crop, which is a pouch or enlargement of the esophagus that can store food. The crop is a very common location for yeast overgrowth/infections.

Other names for yeast infections in birds include:

  • Crop mycosis

  • Thrush

  • Ingluvitis (crop infection)

  • Sour crop

Symptoms of a Yeast Infection in Birds

  • White mouth lesions—initially thick white membranes/covering in the mouth that can progress to ulcers

  • Lethargy

  • Lack of appetite

  • Ruffled feathers

  • Slow growth/development in young birds

  • Regurgitation of food after eating

  • Difficulty swallowing

  • Thickened crop (food can stay in the crop longer)

  • Difficulty breathing, including open-mouth breathing

Causes of a Yeast Infection in Birds

Common causes linked to yeast infections in birds include:

  • Weakened immune system due to:

    • Stress

    • Improper nutrition

    • Underlying medical condition

    • Undeveloped immune system (i.e., in a young bird)

  • Poor hygiene of cage, nest, and/or feeding materials

  • Contaminated food and water sources

  • Antibiotics which disrupt the intestinal microbe (fungi/yeast, bacteria) population

  • Intestinal parasites

A bird can ingest yeast orally, since it’s found in many organic materials, such as fruits, plants, soil, and pet bird enclosures. The yeast becomes an issue within the bird during times of stress or if the bird has a compromised immune system. If a bird has a weakened immune system, a yeast infection can grow.

Many species of birds have a crop, which is a pouch or enlargement of the esophagus that can store food. The crop is a very common location for yeast overgrowth/infections.

The respiratory and digestive tracts have immune cells present on their surfaces that help prevent most yeast (or other disease-causing agents) from causing an infection in a bird. However, a bird suffering from any stress, low immune function (sick or young birds), nutritional deficiencies, or other diseases can be susceptible to a yeast infection.

How Veterinarians Diagnose Yeast Infections in Birds

During a bird’s examination, your veterinarian will perform a thorough physical assessment and collect information on the bird’s history and environment. Questions your veterinarian may ask related to yeast infection in birds may include:

  • Have there been any changes in your bird’s behavior, energy level, or diet?

  • Has your bird been on any medications, supplements, or water additives?

  • What do you use to clean your bird’s bowls/dishes, toys and cage? How often are they cleaned?

In addition to the physical exam, your vet may also perform:

  • Blood work to measure health of internal organs, nutrient deficiencies, and observe signs of other infections (bacterial or viral)

  • Gram’s stain to identify yeast cells under the microscope

  • Swab collection

    • Yeast culture—sample is incubated and grown to identify the type of yeast under a microscope

    • Polymerase chain reaction (PCR)—samples examined for genetic material

If your pet birds, chickens, pheasants, or peafowl experience any lesions that resemble a yeast infection, your veterinarian needs to be notified.  There are some diseases that a yeast infection can mimic, especially if the infection is severe, such as fowl pox, vitamin A deficiency, or infectious laryngotracheitis (ILT) in chickens. 

Treatment of Yeast Infections in Birds

Oral medications or injectable treatments can be used for yeast infections in birds, including:

  • Antifungals

  • Chlorhexidine gluconate—hinders yeast growth

  • Metoclopramide—used if regurgitation is present and helps food move down the upper intestinal tract

  • Copper sulfate—inhibits yeast growth

If a bird has progressed to a severe yeast overgrowth in the crop leading to a crop impaction or crop dilation, surgical correction/intervention might be necessary.

Apple Cider Vinegar for Bird Yeast Infections

In mild cases of a yeast infection in birds, the use of apple cider vinegar (ACV) has been shown to lower the pH of a bird’s mouth, oropharynx, and upper gastrointestinal tract (esophagus and crop), which makes it more acidic. ACV has been shown to have an antimicrobial effect directly on Candida albicans, by hindering microbial growth and damaging their cell structure.

Use of ACV or any other treatments for yeast infections in birds must be guided by your veterinarian. Each bird’s species, size, and lifestyle are taken into consideration before any treatment is recommended.

As a pet parent, you know your bird best. Any changes in their routine, behavior, or eating habits should be discussed with your vet team before starting any treatment for a yeast infection.

Recovery and Management of Yeast Infections in Birds

Most birds can make a full recovery from a yeast infection in one to three weeks.

Focusing treatment on the underlying cause of immune suppression or stress in the bird is key to a successful recovery and to prevent further yeast infections.

Severe yeast infections may lead to ulcerations of the mouth and upper digestive tract. These lesions can cause bacterial infections, in addition to the yeast growth.

Slow crop emptying and sour crop can lead to:

  • Thickening of the crop mucosa (inner lining)

  • Loss of muscle tone of the crop

  • Weight loss

  • Death

Prevention of Yeast Infections in Birds

Proper nutrition, providing a clean, safe enclosure, and limiting any stressors in their environment are the best ways to prevent a yeast infection in birds.  

Nutritious diet options for chickens and other poultry include:

Routine veterinary care should be performed one to two times per year for all birds. Any changes observed in your bird should be evaluated by your veterinarian to identity any underlying diseases early.


Harrison G, Lightfoot T. Clinical Avian Medicine Avian Infectious Diseases. Saunders Manual of Small Animal Practice (Third Edition). 2006.

Hess L. Pet birds need fewer seeds, more formulated diets. DVM360. 2023.

Hopps S. Mycotic Disease of Pet Birds. Merck Manual: Veterinary Manual. 2022.

Jones M. Fungal diseases of pet birds: recognize infection early. DVM360. 2005.

Lightfoot T. Digestive Disorders of Pet Birds. Merck Manual: Veterinary Manual. 2020.

Yagnik D, Serafin V, Shah A. Antimicrobial activity of apple cider vinegar against Escherichia coli, Staphylococcus aureus and Candida albicans; downregulating cytokine and microbial protein expression. Scientific Reports. 2018 Jan 29;8(1):1732.


Jessica Hockaday, DVM


Jessica Hockaday, DVM


Dr. Jessica Hockaday completed her undergraduate degree from California Polytechnic State University, San Luis Obispo, earning a Bachelor...

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