Abstract
This study investigated the effects of sex and age on morphometric traits, carcass characteristics, and the accuracy of logarithmic regression models for predicting body weight from body measurements in Ross 308 broiler chickens. Two hundred 4 week-old chicks (100 males and 100 females) were reared under standard deep-litter conditions in a completely randomized design until 8 weeks of age. At slaughter, males had slightly higher live weight (2585 g vs. 2565 g) and dressed weight (1777.5 g vs. 1660.5 g) than females, resulting in superior dressing percentages (68.78% vs. 64.73%) and breast yield (37.76% vs. 36.06%). Yields of other carcass cuts and offal percentages showed no significant sex differences (p > 0.05). Morphometric traits (body weight, body length, chest girth, shank, wing, thigh, and neck lengths) were significantly influenced by both sex and age (p < 0.001), with males consistently recording higher values. All measurements increased steadily from weeks 5 to 8. Significant sex × age interactions were observed only for body weight and neck length. Logarithmic regression models (Y = a + b ln(X) + e) effectively estimated live weight, particularly using chest girth, which proved the best predictor (adjusted R² = 0.817 in females). Body length and neck length also performed well, while shank, wing, and thigh lengths were poor predictors. Sex-specific models improved prediction accuracy for several traits. In conclusion, male broilers exhibited clear morphometric and carcass advantages. Chest girth offers a reliable tool for farmers to monitor growth and improve production efficiency in Ross 308 broilers.