Sour Crop in Chickens

A fungal yeast causes sour crop in chickens. It is identified by a putrid smell coming up from the crop and out of the chicken’s mouth. Treatment of sour crop is necessary to prevent serious illness.

The crop is part of the oesophagus (food pipe) at the base of the neck and is the first stage of digestion for a chicken; it contains food, water and grit (used for digestion).  When full, the crop is tennis ball-sized. You can sometimes feel the contents of the crop when handling chickens, and it can certainly be seen immediately after a chicken has been eating.

Sour crop in chickens (sometimes called Thrush) is caused by a fungal species of yeast Candida Albicans in the crop. This disrupts the normal bacteria usually found in the crop and leads to a thickening of the crop wall causes problems. If left untreated, death can occur. Sour crop in chickens can easily be identified by the putrid smell from the bird’s mouth.

Sour crop can occur after a course of oral antibiotics (such as Baytril or Tylan) or if there has been a shortage of Vitamin A in the bird’s body, but mouldy/poor quality feeds or strange diets containing the wrong foods are more common. Sour crop appears to be more common in growers than adult birds.

Tip: When is the crop not functioning correctly?

Chickens crops look big when full (up to tennis ball size). It is normal for the crop to expand and contract; it's part of the normal digestion process. It should empty on its own when functioning correctly and there shouldn't be any bad smells. If you are concerned, check the crop has emptied in the morning before a bird has eaten.

Birds digest food differently from mammals, so it helps us to understand how the digestive system of a chicken works.

Sour crop symptoms

The signs of sour crop are straightforward, so this condition is easy to diagnose. There is a terrible smell coming from the bird’s mouth, and once you have smelt it, you will never forget it!

Birds can sometimes be lethargic, dull and will gradually lose their condition.

Sour crop treatment

Unless you are experienced with treating this condition, I advise you to seek veterinary assistance for this condition.

Medicine for sour crop include Nystatin, Ketoconazole, or copper sulphate and possibly a course of antibiotics. All of these medicines are on prescription from a vet.

Orally adding fluids to the crop and then emptying it by turning the bird upside down for short periods (so it doesn’t suffocate) is also possible but does nothing for the infection, and there is a real risk of the bird choking when doing this, which is why veterinary assistance is recommended.

A veterinary procedure would probably use local anaesthetic, cut the crop open, empty it, flush it out with a saline solution, stitch the crop back up and treat the infection.

I have found many references to this condition in pigeons as well as in poultry. Some experienced pigeon fanciers have recommended using garlic. They believe it works faster and better than Nystatin, so it might be worth a try if you cannot get to a vet.

A solution of apple cider vinegar has also been suggested in several online forums with what appears to be mixed results so I can’t say if apple cider vinegar helps to 

I haven’t tried this myself and again would urge you not to let this condition get out of control.

Other useful information:

There are other conditions which can produce similar signs:

  • Impacted Crop where there is a blockage in the crop and the crop is full and feels like dough but doesn't have the smell like sour crop.
  • Pendulous Crop is when the crop becomes blocked and the weight of the food and weak muscles stretch the crop so that it hangs down.
You may also find these articles useful

Related Posts:

Digestive System of a Chicken
Digestive System Problems
The Digestive System of a Chicken

In this article, you will learn about the different parts of a chicken’s digestive system. There are also tips on what to expect from your chickens during normal feeding and digestion.

Read More »
Pendulous Crop

You can feel a chicken’s crop on the lower part of her neck when it’s full after eating. It will empty overnight, but if it becomes blocked, a condition called pendulous crop can occur. 

Read More »

On this page: