Sour crop is a health issue that most bird keepers will encounter at some point while caring for birds. Sour crop can be caused by something as simple as eating long grass, hay or straw. Eating spoiled food matter, or being exposed to unsanitary water or waste from other animals that tend to be vectors for fungus/yeast, like waterfowl. Prevention is always best but despite good efforts the issue can occur. Trichomonas gallinae (Canker) can also cause crop stasis.

What is sour crop? 

Sour crop, also known as crop stasis is caused by yeast (candida albicans) aka thrush that is causing a thickening of the crop wall. This can be caused by factors such as exposure to yeast in what they ingest or due to a blockage from consuming matter that won’t exit the crop like long grass, straw or hay which will cause a yeast bloom in the birds crop over time. When suffering from sour crop birds loose condition, drop weight and often loose interest in food, often they will consume a lot of water, they are dehydrated because food and liquid is not exiting the crop and entering their digestive system.

How does it occur?

Birds must be able to pass what they eat through their crop and into the proventriculus and then on to the gizzard. The gizzard is where food is ground up, it functions similar to our teeth, the grit your birds ingest deposit in the muscle folds of the gizzard and help “chew” the food. Straw, hay and long grass often can’t exit the crop to make it to the gizzard and this causes sour crop. We strongly recommend not using straw or hay in your birds environment for this reason and keeping grass cut to just a few inches high that they have access too. Do not toss lawn clippings into your poultry runs either as this can cause impaction if they consume blades too long to pass. Pine shavings, sand, nesting mats, gravel are all options for where someone would use straw or hay in their setup. 

Another risk factor for sour crop is feeding young birds scratch grains, the whole grains are often difficult to pass through the crop and they may not have consumed enough grit to properly digest the grains which can lead to malnutrition issues. A nutritionally balanced crumble or small pellet is best for young chickens, ducks, guinea, turkeys and other poultry.

Antibiotics can be yet another reason for sour crop. Antibiotics are not very selective in what bacteria they kill so when they are used they kill off the bad AND good bacteria in the system. Disruption of healthy flora is disrupted by this and its a prime opportunity for yeast to bloom and overcome its host. It is STRONGLY recommended to start probiotic treatment for your birds after a course of antibiotics. We offer several probiotic options.

What can I do?

Important steps to prevention are making sure your birds water is clean, use fresh feed and be on the lookout for mold, and keep waterfowl separate from your chickens, turkeys, guinea fowl, pea fowl, etc. as they are often vectors for yeast because of how they interact with water. If you have a climate or housing situation where yeast is a concern you can use Acidified Copper Sulfate monthly in your birds waterers as a prophylactic measure. Acidified Copper Sulfate will help keep yeast count down but if you have a bird that’s crop is not emptying you need to treat them with medications and depending on what caused the blockage, oil and massaging the crop may help get things moving again. 

If you suspect a bird has sour crop feel to see if their crop is bloated or squishy, smell their breath and often when palpating the crop air will be expelled if the crop stasis is do to yeast because its fermenting in their crop. Isolate the bird you are concerned about and withhold food and water till the next morning (or evening if the issue was discovered early in the morning) the birds crop should be empty if its crop is functioning normally, if not you need to treat them.

Medicinal treatment options for sour crop due to yeast is nystatin and ketoconazole. If the cause of your birds crop stasis is trichomonas gallinae then nystatin and an antiprotozoal are a recommended combination. If there is a very foul smell then its likely trichomonas gallinae, if it smells yeasty then the cause it most like candida albicans (yeast). The only way to know what the cause is for sure is to have a lab test done at your veterinarian. If the cause is trichomonas gallinae we offer antiprotozoal options of metronidazole, carnidazole, secnidazole or ronidazole.