Yeast Infection (Candidiasis)

Candidiasis is a yeast infection of the chicken's crop, caused by Candida. It is often recognized by the foul-smelling odor in the crop which you can often smell from the chicken's open mouth.

Yeast infections are caused by crop stasis (when food materials collect in the crop because it isn't emptying properly). Other less frequent causes include:

• Foreign objects
• Antibiotics: Prolonged or inappropriate antibiotic use can disrupt the chicken's natural balance of gut flora and make them more susceptible to Candida overgrowth.
• Corticosteroids
• Poor diet
• Unsanitary conditions: Slimy, unclean waterers
• Crop impaction: Partial or compete blockages in the crop or other parts of the GI tract.

Clinical Signs of Candidiasis

The most common clinical signs observed in chickens with candidiasis include:

• Changes in behavior
• Delayed crop emptying, which after a period of time can lead to the development of a foul smell coming from the chicken's mouth.
• Regurgitation
• Reduced appetite
• Depression/lethargy
• White patches or plaques (oral lesions) on the inside of their mouth and/or under the tongue.
• Abnormal droppings, often appear brownish and watery
• If chicks are affected, may show stunted growth

Chickens with candidiasis can sometimes be concurrently infected with other diseases, which can complicate or confuse clinical signs observed.

Candidiasis Vs Canker

	Candidiasis (Thrush)	Canker
Body areas affected	Oral cavity, esophagus, and crop	Oral cavity, esophagus, and crop
Pathogen type	Yeast	Protozoan parasite
Pathogen species	Candida albicans	Trichomonas gallinae
Oral lesion appearance	Patches of raised, whitish, dead epithelial debris. The top white pseudomembranes can be wiped off.	Sticky, yellowish-white 'canker-like' masses of caseous, necrotic material.
More likely to occur following	Prolonged antibiotic therapy, concurrent disease, infestation with internal or external parasites, or stressful event.	Pigeons and doves sharing the same water or feed source.
Treatment	Treat the primary cause, antifungals, strengthen immunity, crop flush	Metronidazole, thyme extract

Treatment for Candidiasis

In very mild or early cases of candidiasis, all that may be needed is a change in diet and the use of natural remedies, such as apple cider vinegar added to the water. However, once the condition has progressed to a severe infection (once the bird has stopped eating and drinking and is showing obvious lethargy or depression), a trip to your veterinarian is needed.

In severe cases, if the chicken is unable to empty their crop, they may need it emptied and flushed (a procedure that should only be done by a veterinarian, as if it is done wrong, can be fatal to the bird). Concurrent supportive care may be needed as well, in the form of IV fluids, to help restore the natural balance of microorganisms in the crop. Your veterinarian will usually prescribe one of three types of antifungal medications---Nystatin, Ketaconazole, or Itraconazole. There are a variety of different herbs and nutraceuticals that can be given concurrently to help strengthen their immune system but are not cures.