A retrospective review of the histopathology of captive hornbill chicks

Background and objectives: Captive rearing of chicks can be crucial to the success of management plans for endangered species of birds. This study was conducted to document lesions of hornbill chicks to provide information for pathologists and clinicians to improve rearing success in captive hornbills. Methods: Clinical histories and post-mortem reports were evaluated for 40 hornbill chicks (< 3.5 months old), from three species submitted for pathological evaluation to the National Zoological Garden, South African National Biodiversity Institute between 2003 and 2017. The cause of death and histological features present were tabulated. Results: In this group of chicks, 12 (30%) were a week or younger at the time of death. Bacterial infections, especially of the lung and gastro-intestinal tract, were the most common cause of death (38%). Visceral gout, renal tubular degeneration or necrosis, bacterial ventriculitis and pulmonary congestion were the most often recorded lesions. Splenic, thymic and bursal lymphoid depletion and/or necrosis were common. Chicks of all ages commonly showed hepatocyte vacuolar degeneration; and hepatic, renal and splenic haematopoiesis of no pathological significance. Conclusion: This long-term survey in captive hornbill chicks provides baseline information on lesions and conditions seen in these birds and facilitated the formulation of improved captive management manuals of hornbills. Additional detailed postmortem examinations following standardised protocols, including bacterial culture, of hornbill chicks would further improve our understanding of hornbill chick diseases.