Bone tissue exhibits viscoelastic behavior, and stress relaxation analysis provides valuable insight into its time-dependent mechanical performance. This study aimed to evaluate the effects of allicin supplementation on the mechanical and viscoelastic properties of tibial bone in Bovans Brown laying hens. Tibiae of 68-week-old hens were subjected to three-point bending tests to determine quasi-static mechanical properties, as well as stress relaxation tests conducted at three deformation velocities (0.1, 1, and 10 mm/s). Stress relaxation behavior was described using a five-parameter generalized Maxwell model. Allicin supplementation resulted in significantly greater bone stiffness and work to fracture compared with the control group. Stress relaxation tests demonstrated a rate-dependent viscoelastic response in all samples. Bones from allicin-supplemented hens exhibited higher force levels during the relaxation period and reduced stress decay, indicating enhanced elastic behavior and decreased viscous deformation. Model analysis revealed a tendency toward higher equilibrium modulus values and longer relaxation times in the supplemented group, particularly at low deformation velocities. However, no statistically significant differences were observed for E0, τ1, and τ2 between the tested groups. These findings suggest that allicin supplementation may improve bone mechanical and viscoelastic properties in laying hens.