Sour Crop in Chickens – Causes, Recommended Treatment and Prevention in 2024

Suspecting sour crop in chickens and wanting to find out more? We have put together all the information you need to find out more about this condition affecting chickens including how to spot the classic symptoms and ways to treat at home.

sour crop in chickens
Sour crop results in an overgrowth of candida bacteria in chickens crop. This is often felt as a balloon like mass at the front of their body just below their neck.

A chickens crop is an essential part of the digestive tract where the chickens food is held. The crop when healthy has a balance bacteria that helps with digestion, unfortunately this balance can sometimes become too disrupted which causes an overgrowth of yeast and causes discomfort and illness for your chicken.

Sour crop is an infection caused by Candida albicans, a form of yeast that is known to cause thrush in humans. As in humans, candida is a naturally occurring bacteria. Usually, it is kept under control, but may become a problem when the bacteria “blooms.”.

The smell that comes with this condition is reminiscent of “sauerkraut” or “sour milk” left out for too long. The smell comes straight from your chickens’ mouth (actually from the crop) where the fungus Candidia albicans likes to take hold. 

Normally, a chicken’s crop has a pH of around 5.5, which is on the acidic side of the pH scale, to assist with the breakdown of food. Bacteria thrives in the crop, as it is integral to the digestive process. Should the acidity levels change too much, it can upset the balance of good and bad bacteria, causing candida to proliferate and become overgrown.

This then causes the crop walls to become inflamed, making it harder for the food in the crop to pass through. Digestion problems are often the result. If a chicken then cannot empty its crop, their condition will get worse and if not address may end up in death.

Thankfully this condition is not contagious and will only affect the bird that has developed the Candida overgrowth in their crop.

Source: Dr. Gabriel Sentíes-Cué, UC Davis-CAHFS. 

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Symptoms of Sour Crop in Chickens?

Your chicken may be suffering from sour crop if you notice the following symptoms –

  • The chicken will have a depressed demeanor, sunken eyes, decreased appetite and may also have regurgitation.
  • The crop feels like a balloon which has filled with water. Gentle pressure applied to the crop when picking the hen up may cause fluid to spill out from her beak.
  • Classic sour crop has a foul smell and the fluid which is voided is often brown, although this is not always the case.
  • The hen may frequently flick her head.
This chicken has sour crop. Notice the head flick it does right at the beginning of the video which is one of the main symptoms of sour crop.

Causes of Sour Crop in Chickens

  • Ingesting food and water contaminated with feces. 
  • Damp or mouldy feed.
  • Following a course of antibiotics.
  • A weakened immune system will make a chicken susceptible to sour crop. This can occur due to concurrent viral, parasitic or bacterial infections, malnutrition (specifically a vitamin A deficiency).
  • Sour crop is also often secondary to other issues and may recur if the underlying cause is not discovered.
Moldy feed can be a cause of sour crop in chickens

How to Prevent Sour Crop in Chickens

Keep a clean and mold-free environment for your chickens to minimize their exposure to developing sour crop.

This means minimizing stress, vaccinating for viral infections, offering a balanced diet and minimizing exposure to mold and bad bacteria by keeping their food, water and litter fresh and free of contamination. Storing feed in weather-proof, rodent-proof containers is a smart idea to help prevent this.

A balanced diet can help prevent infection, too. By feeding a high quality commercial feed your birds’ nutritional needs should be met. 

If your birds are not getting a balanced diet from a high quality commercial feed (from too much scratch or other scraps), a vitamin A deficiency in particular could pre-dispose your birds to sour crop. 

Ensure you give your chickens a probiotic following any course of antibiotics to help restore beneficial bacteria into their digestive system.

Some people like to put apple cider vinegar into their chickens water or occasionally feed their flock Greek yoghurt to help with probiotic dosage and maintenance from these naturally probiotic rich foods.

Keeping your chickens feed and living space dry and mold free will help prevent cases of sour crop

Treating Sour Crop in Chickens

There are steps you can take at home to treat your chickens sour crop.

If your chicken seems to have advanced symptoms or is looking very poorly its best to seek veterinary advice, especially if you still unsure if your chicken is presenting with sour crop.

For an at home remedy you may try the following treatments to rid your chicken of sour crop:

Apple Cider Vinegar/Yoghurt Solution

  1. Withhold food and water for 24 hours to allow the crop to naturally empty as much as possible.
  2. On an empty crop, dose apple cider vinegar (diluted to the manufacturers recommendations) or a Greek yoghurt with a high probiotic count, syringed into the side of the beak.
  3. 12 hours after the apple cider vinegar or yoghurt administration a few sips of tepid water can be offered together with a small amount (teaspoon) of soft solid food.
  4. Monitor to check the sour crop does not return and gradually build up to normal rations of feed and water.

Epsom Salt/Copper Sulphate Solution

  1. Mix 1 teaspoon of Epsom Salts in half a cup of water. Pour or squirt down the birds through twice a day for 2-3 days.
  2. Mix half a pound of copper sulphate, half a cup of apple cider vinegar and half a gallon of water together in a container.
  3. Add 1 tablespoon of the solution per gallon of water into your chickens waterer.
  4. Keep this up until the sour crop is resolved.
  5. Follow up with probiotic rich treats like a little greek yoghurt or fermented vegetables such as sauerkraut (these are treats and should not make up more than 10% of your chickens daily diet).
Adding copper sulphate and vinegar solution to your chickens waterer can help clear a sour crop infection


Water Belly is a serious health condition that chickens can face. Learn how to treat this condition at home by reading our guide here.

Chicken Care Shopping List

Are you looking for a shopping list of everything you need when caring for your precious flock? We have put together an easy reference of items for your convenience. 

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The team at My Chicken Guide are chicken enthusiasts! Our team has over 20 years experience in raising and caring for chickens. Our head writer is a qualified Environmental Scientist with a passion for sharing science based information on chicken care.

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