October 2026 | Advanced Surgical & Anesthetic Techniques in Poultry Models: Tendon Repair and Species-Specific Stabilization

VITALS Deep Dive Article — by Niki DeValk, AAS, LVT, SRS

Interventional & Surgical Specialist | Owner, NiKara Preclinical

Poultry species, particularly chickens and turkeys, are increasingly used in tendon and orthopedic preclinical research due to favorable cost, availability, and anatomical relevance of the digital flexor tendon to human hand tendon repair. However, avian anesthetic and surgical management differs substantially from mammalian practice, and misapplication of mammalian assumptions is a common source of avoidable complication. This review synthesizes current literature and practitioner experience on avian respiratory physiology, tendon repair surgical technique, anesthetic protocol selection, intraoperative monitoring, analgesia, and post-operative stabilization, with the aim of providing programs new to poultry models a structured, evidence-informed starting point.

Poultry occupy an unusual position in preclinical research: widely used in tendon and orthopedic studies, yet rarely covered in standard veterinary technician training. Most personnel entering this space come from a mammalian background, and the gap between assumptions that transfer and those that do not is where most early complications originate. Nowhere is that gap more consequential than in respiratory physiology. Unlike the bidirectional, tidal ventilation of mammals, birds move air unidirectionally through a system of air sacs and parabronchi. This distinction is foundational to safe anesthetic management: airway positioning, interpretation of capnography and pulse oximetry trends, and even routine surgical positioning all require reconsideration rather than direct carryover from mammalian protocols. Restrictive positioning that compresses the air sacs — including tight wrapping or inadequate sternal support — can meaningfully impair ventilation in ways that would not be clinically significant in a mammalian patient, and should be treated as an active monitoring concern throughout a procedure rather than a fixed setup decision.

Against that physiologic backdrop, the surgical rationale for poultry tendon models becomes clearer. The chicken digital flexor tendon has become a widely used research model because its fibro-osseous canal and synovial sheath anatomy closely parallel the human hand, allowing reasonable generalization of suture technique, gliding resistance, and adhesion outcomes.¹ Current literature continues to use this model both to validate new core suture and epitendinous repair techniques and to examine how operator experience level affects repair quality and biomechanical strength¹⁷ — relevant context for programs using poultry models for technique validation or training in addition to primary study endpoints. Turkeys extend this same logic to procedures requiring larger tendon diameter or heavier orthopedic hardware, and have also been used in tendon transfer and nerve-tendon interface research.³

Anesthetic management in this species also demands its own logic rather than a mammalian one. Both injectable and inhalant approaches appear in current literature, each with distinct trade-offs. Ketamine-based injectable combinations (with xylazine or midazolam) have been directly compared against inhalant isoflurane for procedures such as stereotactic surgery in broilers, with differing induction and recovery profiles between approaches.⁶ Inhalant maintenance — isoflurane or sevoflurane — remains the more common choice where precise depth control and rapid recovery are priorities.⁵ Recent bispectral index (BIS) work in chickens has helped quantify how anesthetic depth correlates with heart rate, blood pressure, and clinical signs across different agent and adjunct combinations.⁴ Across the literature, the consistent finding is that the margin between an adequate surgical plane and cardiovascular compromise is narrower in poultry than in most mammalian species used in preclinical work. Turkeys, being larger and somewhat more cardiovascularly robust, tend to tolerate a marginally wider range than chickens, but in both species, doses should be titrated to individual patient response rather than applied as a fixed protocol. (This article is intended as an educational overview, not a dosing reference. Anesthetic protocols should always be developed and adjusted in consultation with the attending veterinarian and under an IACUC-approved protocol.)

That narrow margin has direct implications for how a case is physically managed. Poultry lack the soft tissue padding mammals have over bony prominences, making positioning aids and careful keel and limb support essential to prevent pressure injury during longer procedures. Traction during tendon handling should be light and controlled, as surrounding fascial planes are thinner and less forgiving of aggressive retraction than in canine or porcine models. Continuous monitoring — temperature, heart rate, respiratory pattern, and depth-of-anesthesia monitoring where available — is critical given how quickly avian patients can shift anesthetic planes. Analgesia follows the same species-specific logic: opioid analgesics, particularly butorphanol, have demonstrated clinical benefit in poultry, with comparative work on morphine and butorphanol in broilers supporting effective pain control without excessive sedation.¹⁸ Multimodal analgesic strategies — combining systemic opioids with local or regional techniques where feasible — are increasingly described in the avian anesthesia literature, mirroring the multimodal shift already established in mammalian species.

The work is not finished when the procedure ends. Species-appropriate external stabilization must account for a patient that will attempt to bear weight and ambulate far sooner than most mammalian post-surgical patients. Housing design is equally consequential: perch height, substrate, and enclosure size should be adjusted to minimize load on the repair while still allowing the bird to express normal behavior, since prolonged immobilization carries its own welfare and healing costs in this species. Chickens and turkeys typically return to ambulation and normal behavior faster than mammalian orthopedic patients — part of what makes them attractive as a model, and part of what makes inadequate stabilization especially risky. Close early monitoring of gait, weight-bearing, and toe position (a documented indicator in tendon transfer literature) helps identify problems before they compromise the repair.³

Taken together, these considerations explain why the field continues to move toward poultry tendon and orthopedic models. Cost, availability, anatomical relevance to human tendon structure, and faster study timelines continue to drive interest. The trade-off is a steeper learning curve around handling, physiology, and species-specific post-operative care — precisely where programs new to poultry most often encounter avoidable complications. Partnering with personnel who already hold hands-on poultry surgical and anesthetic competency, rather than acquiring it study by study, meaningfully reduces this risk. Poultry tendon and orthopedic models offer genuine scientific and practical advantages, but only when physiology, handling, and post-operative planning are treated with the same rigor applied to any other species — adapted to avian anatomy and behavior rather than assumed from mammalian experience.

This article reflects current peer-reviewed literature and practitioner experience; it is intended for professional and educational use and is not a substitute for a study-specific, IACUC-approved anesthetic or surgical protocol.

References

1. Karanfil E, Özlen ÜO, Berker B, et al. Measuring resident experience level in an in-vitro organic tendon repair model. Düzce Tıp Fakültesi Dergisi. 2026;28(1):52-56.

2. Little D, Amadio PC, Awad HA, et al. Preclinical tendon and ligament models: beyond the 3Rs to 5W1H. J Orthop Res. 2023. doi:10.1002/jor.25678.

3. Browning GR, Le AH, Warnock JJ, Balasubramanian R. An investigation of a novel tendon transfer surgery for high median-ulnar nerve palsy in a chicken model. J Invest Surg. 2019;32(1):39-47.

4. Velasco Gallego ML, Martin Jurado O, Hatt JM. Effects of isoflurane and sevoflurane alone and in combination with butorphanol or medetomidine on the bispectral index in chickens. BMC Vet Res. 2021;17(1):1-11.

5. Anjana RR, Parikh PV, Mahla JK, et al. Comparative evaluation of isoflurane and sevoflurane in avian patients. Vet World. 2021;14(5):1067-1073.

6. Rahdari A, Hamidi F, Ghasemi S. Comparing injectable anesthesia regimes of ketamine-xylazine, ketamine-midazolam, and inhalation using isoflurane in broiler chickens to perform stereotactic brain surgery. J Vet Res. 2024;79(2):81-89.