Distraction osteogenesis in a juvenile rooster (Gallus gallus domesticus) with mandibular fracture malunion

Treatment of avian malocclusion, or "scissor beak," is well-described in the literature, but reports have focused on early intervention of acute traumatic and congenital cases, and surgical correction of chronic mandibular malunion are rare. This report describes the diagnostic investigation, surgical correction, and long-term follow up of a 3-month-old Ameraucana rooster (Gallus gallus domesticus) with chronic beak malocclusion. Computed tomography was used to confirm the unilateral mandibular fracture malunion and guide surgical planning, which involved creation of a custom osteogenic distractor. The surgery consisted of mandibular osteotomy, placement of an external skeletal fixator, and placement of a feeding tube. Gradual distraction was applied every other day starting three days after surgery. A combination of analgesics, antibiotics, and assisted feeding was used during the distraction process. By 14 days post-operatively, radiographs revealed appropriate bone callus formation and implant-associated lucency, which raised concern for osteomyelitis. The external fixator and feeding tube were removed 21 days post-operatively, with beak function returning to normal and significant correction of the malocclusion. At 28 months post-operatively, the beak remained functional, requiring infrequent beak trims. This case report provides insights into the diagnosis and successful treatment of mandibular fracture malunion in a chicken, adding to the body of literature of malocclusion management.