Infectious Bursal Disease (IBD/Gumboro) is a highly contagious viral disease targeting young chickens' immune systems, causing mortality and leaving survivors permanently immunocompromised.
IBD causes rapid, severe disease in young chicks. Affected birds show depression, ruffled feathers, inability to eat or drink, and severe hemorrhages in muscle tissue. Death rates can be substantial within days of outbreak onset. Survivors face a lifetime of immune compromise, meaning they suffer more severely from diseases that healthy birds would resist. This hidden, ongoing welfare impact is often overlooked in assessments focused only on acute mortality. The permanent immunosuppression also means survivors require more antibiotic treatment, raising both welfare and antimicrobial resistance concerns.