Integrating hemp cake in organic layer diets: a comprehensive assessment of egg quality, hen behavior, production costs, and life cycle impact

This study evaluated the effects of incorporating 30% locally produced hemp cake into the diet of organically reared laying hens. A total of 280 Hy-Line Brown hens (18 weeks of age) were randomly allocated to two dietary treatments: a commercial control diet based on sunflower cake and soybean seeds as the main protein sources (Control_D), and an experimental diet in which these ingredients were partially replaced with 30% locally produced hemp cake (Hemp_D). Each treatment consisted of two replicate pens of 70 hens, and data were collected over a 16-week experimental period following dietary adaptation. Egg production was recorded daily, whereas egg quality was evaluated at the end of the experimental period. Behavioral time budgets were analyzed using instantaneous scan sampling, while production costs per egg and environmental impact were estimated through feed-cost analysis and life cycle assessment, respectively. The Hemp_D did not affect laying performance, egg weight, or egg mass. Yolk fatty acid composition was significantly modified by hemp cake inclusion, with higher polyunsaturated fatty acids, increased omega-3 content, and a lower n-6/n-3 ratio, whereas egg physical traits and sensory acceptability were largely unaffected. Hen behavior and spatial distribution were not influenced by diet. The inclusion of hemp cake increased feed-related production costs and the CO2-equivalent environmental impact compared with Control_D. Overall, hemp cake can be included at high levels in organic laying hen diets without impairing performance, behavior, or egg sensory quality, while improving egg nutritional value. However, the environmental and economic outcomes underscore the need for targeted policy measures and continued research aimed at optimizing hemp cultivation practices and reinforcing sustainable, locally based feed supply chains.