Crop (Ingluvies) in Chickens: Digestion & Stasis
Detailed physiological overview of temporary feed storage, sour crop, and impaction.
Scientific Overview
The crop (ingluvies) is a thin-walled, muscular pouch located on the right side of the base of the chicken's neck. It is a biological adaptation allowing birds to gather food rapidly in the wild and digest it slowly in safety.
Ingluvies Function and Softening
The crop stores feed when the proventriculus and gizzard are full. Saliva and water consumed by the bird moisten and soften the hard grains. While no digestive enzymes are secreted by the crop itself, amylase from saliva and lactic acid bacteria initiate fermentation, beginning carbohydrate breakdown.
Pathology: Sour Crop & Impaction
Two common disorders affect the crop: Sour Crop (candidiasis, a yeast infection caused by Candida albicans, leading to a squishy, fluid-filled crop that smells sour); and Crop Impaction (stasis, where long grass, string, or dry feed blocks the exit, causing a hard, solid mass that starves the bird). Crop stasis must be cleared surgically or massaged with water.
All scientific data, diagnostic criteria, and performance benchmarks presented on this page are derived from published peer-reviewed journals and official veterinary codes:
- Avian Pathology & Diagnostics: World Organisation for Animal Health (WOAH, 2023). Manual of Diagnostic Tests and Vaccines for Terrestrial Animals. Paris, France.
- Poultry Diseases & Histology: Swayne, D.E., et al. (2020). Diseases of Poultry (14th ed.). Wiley-Blackwell / American Association of Avian Pathologists.
- Nutrition & Feed Chemistry: Leeson, S. & Summers, J.D. (2001). Commercial Poultry Nutrition (3rd ed.). University Books, Guelph, Ontario.
- Commercial Breed Standards: Aviagen (2024). Ross 308 & Cobb 500 Broiler Performance Objectives. / Lohmann Breeders (2024). Lohmann Brown Management Guide.