A novel photoperiod-sensitive laying curve for modelling egg production in native chickens and the effect of black soldier fly larvae supplementation under agroecological conditions

Native chicken breeds are disadvantaged when evaluated with tools designed for commercial hybrids, as they produce over multiple laying cycles and exhibit seasonal laying variations under extensive conditions. This study used a ‘Rustic-Seasonal’ predictive model to characterise egg production in the endangered Millefiori Piemontese, a dual-purpose Italian breed, over a complete first laying cycle (31–66 weeks of age) under low-input conditions, natural photoperiod and no climate control. The effect of supplementing the diet with dehydrated black soldier fly larvae (BSFL) at 15% of actual daily dry matter intake was also assessed. Seventy birds (60 hens, 10 roosters) were allocated to ten floor pens and assigned to a control (C) or BSFL-supplemented diet (EXP). BSFL supplementation significantly reduced basal feed consumption by 5.8% without compromising production, and tended to increase laying rate (58.4 vs. 55.3%; P = 0.078); the overall feed conversion ratio was not significantly affected. The Rustic-Seasonal model, incorporating a cosine photoperiod modulator into the Wood framework (R² = 0.992, RMSE = 1.4%), projected, under literature-based inter-cycle assumptions, a three-cycle lifetime production of approximately 397 and 419 eggs per hen for C and EXP, respectively. These findings provide a framework for evaluating photoperiod-sensitive genotypes.