Necropsying a Chicken: The Internal Organs
You may want to review chicken anatomy before you make your first cut. As you perform the steps, jot down notes about anything that puzzles you during the necropsy. Describe the color, size, texture, and location of the things you saw in simple terms so that you can look up your findings later or describe them to your chicken health advisor. The following steps help you with the internal examination.
To position the bird, place the bird on its back with the legs toward you.
Grasp both legs and push them down toward the table to flatten the legs away from the body.
The hip joints will pop when you’ve done this correctly.
To open the abdomen and chest cavity, pick up the skin over the abdomen with your fingers to make a tent and cut through the skin with your scissors.
Using your hands, peel the skin up toward the head to expose the breast.
Look at the breast muscle. Is the keel bone prominent because the breast muscle is shrunken? Is the breast muscle pale or bruised?
Cut through the ribs and muscle on the sides of the keel.
Grasp the lower point of the keel and pull upward to lift the breast and expose the internal organs in the chest and abdomen.
Identify the liver, which is a large, dark red organ.
The normal-sized liver shouldn’t extend past the tip of the breast. Check the liver for white or yellow spots and lumps that may indicate infection or tumors.
Make sure the abdominal cavity is free of fluid and looks clean.
Blood or blood clots in the abdomen can signal fatty liver hemorrhagic syndrome. Gunk that looks like scrambled egg floating in the abdomen is a sign of egg peritonitis. Lots of clear, yellowish-tinged fluid indicates a condition called ascites.
Try to find the air sacs.
Normal air sacs look like soap bubbles or clear cellophane wrap. Cloudy or gunky air sacs are a sign of a lower respiratory tract infection.
Remove the liver, gall bladder, and spleen.
The spleen is a round, reddish organ located near the stomachs, and the gall bladder is nestled in the center of the liver — a little green discoloration in that area is normal.
Remove the heart, which is encased in a thin, almost see-through membrane.
Cut through this membrane to view the heart’s outside surface. A little clear fluid between the membranous heart sac and the heart is normal. A lot of fluid in the sac or a cloudy, rough surface on the outside of the heart indicates an infection.
Find the place where the esophagus enters the stomachs (the proventriculus and gizzard).
Cut through the esophagus. Lift the guts — the stomachs, intestines, and ceca — out of the abdomen as you trim the thin membrane that holds them inside the abdomen. Cut through the large intestine where it exits the body at the vent, in order to free the whole package of guts from the abdomen. Set the digestive tract aside for a closer look later.
Inspect the organs close to the backbone.
The kidneys are embedded along each side of the backbone. A normal pair of kidneys is elongated, dark reddish-brown, and symmetrical. Feel the kidneys, and cut into them to look for crunchy, whitish kidney stones.
Find the reproductive organs.
In roosters, a pair of whitish bean-shaped testicles is located above the kidneys. In hens, the left ovary, which looks like a bunch of orangey-yellow grapes, is positioned on top of the left kidney. (The right ovary doesn’t develop in female chickens.) You may find an egg under construction within the oviduct.
Using your fingers, tease the lungs away from the ribcage.
They should be light pink and spongy.
Go back to the digestive tract that you removed earlier and, starting at the stomach end, cut along the entire length of the digestive tract toward the cloaca at the vent end.
You’ll be cutting through the proventriculus, gizzard, and small intestine. Also cut open each of the two ceca and lay them open. The gizzard is muscular and tough to cut, and it’s normal to find grit (small stones) inside.
Rinse the lining of the stomachs, intestines, and ceca with water to flush away the contents for a better view.
Look for bleeding and thickened red patches in the lining of the gut that are tip-offs for coccidiosis. You may also see intestinal worms waving at you.
Search for the bursa of Fabricius.
In a chicken less than 4 months old, you may be able to find this important organ of the growing bird’s immune system when you cut through the cloaca at the end of the digestive tract.
A normal bursa is a small, grape-like pouch with a wrinkled, cream-colored interior. Infectious bursal disease causes redness and jelly-like swelling of the bursa.