Effect of Different Dietary Doses of Black Soldier Fly Meal on Performance and Egg Quality in Free-Range Reared Laying Hens

(1) Background: Given the problems currently posed by the use of soybean meal in poultry feeding, its replacement with black soldier fly (BSF) meal may be a suitable strategy. Therefore, this study evaluated the effect of this dietary replacement on laying performance, egg quality, and yolk nutritional composition in free-range reared hens. (2) Methods: Three diets were formulated: a control diet with 210 g/kg of soybean meal, a diet with 105 g/kg of soybean meal and 80 g/kg of BSF meal, and a diet with 160 g/kg of BSF meal. This eight-week-long study was performed with 126 Bovans Brown hens aged 36 weeks (six replicates of seven hens each per dietary treatment); (3) Results: The laying performance of hens was not influenced by the diet consumed. Neither was the yolk content in fat, protein, cholesterol, choline, B vitamins, and cholecalciferol affected. The dietary inclusion of BSF meal made yolk colour score and albumen Haugh units decrease (p < 0.001) by 51.1% and 12.0%, respectively. It also reduced the yolk content in retinol (by 10.1%, p = 0.0037), but it increased that of alpha- and gamma-tocopherol (by 27.6%, p = 0.014, and 25.8%, p = 0.0077, respectively). A negative linear effect (p < 0.001) was observed on yolk zinc concentration and on the proportions of polyunsaturated and omega-3 fatty acids with increasing dietary dose of BSF meal; (4) Conclusions: Soybean meal could be fully replaced by BSF meal in the diet of hens without affecting the laying rate or the egg weight. However, the dietary inclusion of BSF meal led to paler yolks and impaired albumen quality, while it decreased the content of retinol and zinc and the proportions of polyunsaturated and omega-3 fatty acids in egg yolk.