During a poultry necropsy, the trachea is routinely opened to inspect it for mucus, blood, inflammation (tracheitis), or other lesions.

The general procedure is:

1. Place the bird on its back and reflect the skin from the neck to expose the trachea.
2. Identify the trachea—it is the firm, ribbed tube with cartilaginous rings running down the neck. (The esophagus is softer and lies alongside it.)
3. As an alternative, leaving the skin in place, use fine scissors to make a longitudinal incision from the edge of the mouth along the oesophagus. Next, locate the glottis and insert one blade of the scissors into the opening of the trachea. Cut the trachea longitudinally from the glottis to its bifurcation, where it divides into the two primary bronchi. Cut along only one side of the tracheal wall so that the trachea can be opened by gently pushing it from beneath with a finger, allowing it to open like a book for examination of the mucosal surface.
4. Keeping gentle pressure with one finger from beneath, spread the trachea open and examine the mucosal lining. Look for:
   • Excess mucus or froth
   • Blood or hemorrhage
   • Thickening of the mucosa
   • Caseous (cheesy) material
   • Parasites (e.g., gapeworm in appropriate settings)
   • Discoloration or necrotic lesions
5. Continue the examination down to the syrinx (the junction where the trachea divides into the bronchi), as some diseases produce lesions there.

If additional diagnostic tests are required, collect short transverse sections of the trachea for histopathological examination. For PCR testing, press an FTA card firmly against the exposed tracheal mucosa to collect a sample.

Histopathological examination is typically used to confirm ILT, whereas PCR testing can aid in confirming IB, ND, or aMPV infections. For further details on sample collection, interpretation, and diagnosis, refer to the relevant chapters of this book.