Tarsus length as a simple and robust candidate for early sex determination in partridges across contrasting growing contexts: a case study in Rock partridge (Alectoris graeca Meisner, 1804)

) reared under contrasting production systems (intensive vs. semi-natural). A total of 33 chicks were included. Body weight and linear body measurements were systematically recorded, and multivariate discriminant analysis was used to identify the most informative traits. Live weight, tarsus length, and head length emerged as the main predictors of sex. The most efficient and easily transferable discriminant model was obtained at 42 days post-hatching using tarsus length as the sole variable, achieving a high canonical correlation (0.89) and 100% classification accuracy under the present experimental conditions, regardless of the rearing system. The proposed approach identifies a practical, rapid, and low-cost candidate for early sexing of juveniles, showing consistent performance across rearing conditions and offering direct applications for breeding management, production planning, and veterinary supervision of captive-reared birds intended for release.