Why do drooling and air swallowing symptoms occur in three-day-old broilers due to incorrect spray bronchitis vaccination?

Drooling, air swallowing, and chirping in three-day-old broilers after spray vaccination may indicate respiratory distress due to a reaction to the vaccine.

In the spray method of vaccine administration, if the particle size is smaller and below 100 microns, the problem of water pulverization and penetration of the spray into the lower respiratory tract is likely to exacerbate respiratory symptoms and cause discomfort and air swallowing symptoms as the chicks attempt to clear their airways.

Fine aerosols penetrate deeper into the lower respiratory tract and air sacs, while larger droplets tend to deposit in the upper respiratory tract and eyes. Controlled particle size and spray techniques are critical for effective delivery and to prevent adverse reactions due to deep lung deposition.