• 16 parts
  • Checked September 2026

Bird Digestive System Diagram

The digestive tract of a chicken, beak to cloaca, then the gizzard cut open.

Bird Digestive System Diagram

Name Date

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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
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Write the name of each numbered part.Answer key

  1. Beak
  2. Esophagus
  3. Crop
  4. Proventriculus
  5. Gizzard
  6. Liver
  7. Gallbladder
  8. Duodenal loop
  9. Pancreas
  10. Small intestine
  11. Ceca
  12. Large intestine
  13. Cloaca
  14. Gizzard muscles
  15. Koilin lining
  16. Grit

Drawn for this site on 2026-09-30 from plain geometry. Licence: own work.

Each numbered ring is a button. Use the arrow keys to move between them and Enter to choose. Names are read out in Study, and once a part is answered.

Next step Next: the digestive system of a pig

All 16 parts on the diagram

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The tract in the bird 13

  1. Beak A chicken picks up its feed with its beak. It has no teeth and cannot chew; the tongue pushes the feed back to be swallowed.
  2. Esophagus A flexible tube. It carries feed down from mouth to crop. From the crop it carries feed on to the proventriculus.
  3. Crop An out-pocketing of the esophagus at the base of the neck. Feed and water are stored here; very little digestion takes place in it.
  4. Proventriculus The glandular stomach, also called the true stomach. Acid and digestive enzymes are added to the feed here, before it is ground.
  5. Gizzard The muscular stomach, also called the ventriculus. Two sets of strong muscles grind the feed, doing the work of teeth, and a thick lining protects them.
  6. Liver In two lobes, which lie partly round the gizzard. It makes bile, which helps digest fats.
  7. Gallbladder A small sac on the liver's right lobe that stores bile. The bile reaches the duodenum through a duct.
  8. Duodenal loop The first part of the small intestine, also called the duodenum. A long loop that leaves the gizzard, runs back and returns.
  9. Pancreas A long, thin gland between the two limbs of the duodenal loop. Its digestive juices pass into the duodenum.
  10. Small intestine The duodenal loop is its first part. The rest, the jejunum and ileum, is where most of the nutrients are absorbed.
  11. Ceca Two long blind pouches leaving at the join of small and large intestine. Coarse material left in the feed ferments in them.
  12. Large intestine Short and nearly straight, despite its name. The last of the water is taken back here.
  13. Cloaca The chamber at the end of the tract. Digestive waste mixes here with the waste of the kidneys, and both leave together.

Inside the gizzard 3

  1. Gizzard muscles Two sets of strong, thick muscles. They squeeze and grind the feed, doing the work of teeth.
  2. Koilin lining A tough layer that lines the gizzard. It protects the gizzard's muscles from the grinding. Older books call it the horny lining.
  3. Grit Small stones the bird has swallowed. The gizzard's muscles work the feed against them, and they stay until they are ground small enough to pass on.

How this list was compiled: Every name checked on 2026-09-30 in two sources. poultry.extension.org, Avian Digestive System, by Dr. Jacquie Jacob of the University of Kentucky: every part of the chicken's tract and what it does, https://poultry.extension.org/articles/poultry-anatomy/avian-digestive-system/. O. C. Bradley, The Structure of the Fowl (1915, public domain): crop, glandular stomach, gizzard, the duodenal loop with the pancreas, liver and gall-bladder, the two caeca, large intestine and cloaca, https://archive.org/details/structureoffowl00brad. Wikipedia, Bird anatomy, Gizzard, Crop, Proventriculus and Cloaca, https://en.wikipedia.org/wiki/Bird_anatomy. Licence: own work

The drawing: Drawn for this site on 2026-09-30 from plain geometry; nothing traced. Licence: own work

How it works

This bird digestive system diagram uses a chicken, whose tract is typical of birds. A bird has no teeth: it stores feed in the crop, adds acid in the proventriculus and grinds in the gizzard. It is a plan, not to scale.

Read the full guide

Follow the feed

Beak, esophagus, crop, esophagus again, proventriculus, gizzard. From the gizzard the duodenal loop runs back and returns, with the pancreas between its two limbs. Then come the coils of the small intestine, the two ceca, the short large intestine and the cloaca.

Inside the gizzard

Switch to Inside the gizzard to see how a bird grinds without teeth: two thick muscles, a tough lining that protects them, and the grit the bird has swallowed. Press Quiz me to name each part yourself.

  • Do not mix up the crop and the gizzard. The crop only stores feed; the gizzard grinds it.

Questions and answers

Why do birds have a gizzard?

Birds have no teeth, so the gizzard does the chewing. Its two sets of strong muscles grind the feed, helped by small stones the bird has swallowed.

What is a bird's crop for?

Storage. A bird can eat a lot quickly, hold it in the crop, and digest it later somewhere safer. Very little digestion happens in the crop itself.

Do birds have a stomach?

Yes, in two parts. The proventriculus is the glandular stomach, where acid and enzymes are added. The gizzard is the muscular stomach, where the feed is ground.

Do birds urinate?

Not separately. The waste of the kidneys reaches the cloaca as uric acid and leaves with the droppings, as a white coating on them.

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