Chronic Respiratory Disease is a slow spreading and long lasting respiratory disease that is can lay latent with no symptoms for long periods until times of stress cause it to appear, which can make it more difficult to diagnose. It can be passed slowly through a flock and is also complicated because it can be passed to the next generation through the egg.
When: 3 weeks through adult
Treatment: Antibiotics will only treat the symptoms, but will not prevent spread. A long-term treatment with antibiotics will result in a resistance to it and is not recommended. The only way to guarantee a stop to the spread is to cull the flock, which is not always practical.
Vaccine: Yes (click here for more information)
Also Known As:
Affects: Sinuses, Trachea, Air Sacs
Clinical Diagnosis: Diagnosis by laboratory testing of blood/plasma.
Diseases with similar symptoms: Similar symptoms, but CRD spreads much more slowly within the flock.
Duration of symptoms: 7 to 21 days, however it can be longer.
Incubation: As little as 14 days.
Morbidity: High (Nearly 100%) occurrence in birds that have not been vaccinated.
Mortality: Often low, but higher in young birds.
Transmission to people: No.
Damerow, Gail (1994) The Chicken Health Handbook. North Adams, MA: Storey Publishers