Abstract
<title>Abstract</title> <p>Accurate estimation of live body weight is essential for flock management, health monitoring, and breeding decisions, yet weighing facilities are often unavailable in smallholder poultry systems. Kadaknath, a distinctive fibro-melanotic indigenous chicken breed of India, has received considerable commercial and conservation interest, but information on its morphometric characteristics and body weight prediction remains limited. This study evaluated the relationships between body weight and external body measurements and developed a practical morphometric equation for estimating live weight in Kadaknath chickens. Body weight and 23 external morphometric traits were recorded in 50 Kadaknath chickens (18 males and 32 females) representing young and adult age groups. Descriptive statistics, Pearson's correlation analysis, principal component analysis (PCA), and stepwise multiple linear regression were used to characterize morphological variation and identify predictors of body weight. Mean body weight was 1.00 ± 0.04 kg (range: 0.44 to1.75 kg). Nineteen of the 23 morphometric traits were significantly associated with body weight (P < 0.05), with closed wing length (r = 0.83), back length (r = 0.80), and tarsus circumference (r = 0.77) showing the strongest relationships. Principal component analysis condensed the morphometric dataset into two components explaining 64.97% of the total variance, corresponding broadly to body-frame and appendage dimensions. Stepwise regression identified closed wing length and chest circumference as the most informative independent predictors of body weight and generated the equation BW = -1.133 + 0.067(CWL) + 0.023(CC) (Adjusted R² = 0.757; P < 0.001). Predicted and observed body weights were strongly correlated (r = 0.876), with a root mean square error of 0.149 kg and a mean absolute error of 0.121 kg. Leave-one-out cross-validation confirmed satisfactory model stability, yielding a cross-validated R² of 0.660, prediction correlation of 0.814, RMSE of 0.180 kg, and MAE of 0.134 kg. These results demonstrate that a small number of easily measured body dimensions can provide reliable estimates of live body weight in Kadaknath chickens. The proposed equation offers a simple, low-cost, and non-invasive tool that may assist flock management, breeding programmes, and conservation efforts where access to weighing equipment is limited.</p>