Laryngotracheitis outbreak limited to a part of a chicken flock exposed to smoke and chemicals

Laryngotracheitis was diagnosed in a flock of molted, caged table-egg-layers. Morbidity was restricted to an area of the house in which the birds had been exposed to smoke from a fire in the house and to a powdered chemical fire-extinguisher used on the fire. Mortality in this group began to rise 6 days after the fire and continued to be above normal for about 3 weeks. Feed consumption dropped for about 1 1/2 weeks after the fire but was normal or above normal during the rest of the disease outbreak. Egg production dropped slightly for 1 week after the fire, then returned to normal. Microscopic tracheitis in the exposed birds continued for 11 weeks after the fire. Hens outside of the smoke-affected area did not show histopathological changes or shed laryngotracheitis virus.