Figure 4. Deposition of fluorescent particles in the respiratory tract of 1-day-old (□), 2-week-old (○), and 4-week-old (Δ) broilers. NELTS = nose, eyes, larynx, trachea and syrinx. LT = lungs and thoracic air sacs. LTOC = lower beak, tongue, esophagus and crop. Adapted from Corbanie et al. (2006).