The aim of this study was to examine the effect of cage density and hybrid variety on keel bone damage in laying hens. Methods: In this study, two different hybrids (Hy-line Brown, HB; Isa Tinted, IT) were used and 3 different cage densities low (750 cm2/hen), medium (535.71 cm2/hen) and high (375 cm2/hen) were applied. The research started at the age of 20 weeks and continued until the chickens were 60 weeks old. In the research, 396 chickens (198 HB, 198 IT) and 54 cages were used. Laying hens were grouped by weight prior to cage placement. At the end of the experiment, the body weights of the chickens were measured. Additionally, a total of 54 randomly selected chickens (27 HB, 27 IT) were slaughtered to determine keel bone damage. After euthanization, the skin over the chest area was removed, and the chest structure was examined. The keel bone of the chicken, whose chest area was examined, was removed and scored. The chest area was scored as present or absent for hematoma. A score of “0” was given if no deviation or other damage was present in the chest area. A score of “1” was assigned if there was deviation or other damage (thickened) in the chest area. The keel bone was scored as follows: “0” for no damage, “1”for mild deviation, “2” for moderate deviationor thickening, and “3” for severe deviation or fracture. Results: According to the results of the research, hematoma in the chest area was observed more at low cage density (P<0.001). Additionally, as a result of scoring the chest area and keel bone; it was determined that the most damage was in HBs (P<0.001). Cage density did not affect body weight. Moreover, keel bone damage was found to be more severe in Hy-line Brown hens compared to Isa Tinted hens (P<0.001). Conclusion: In conclusion, keel bone damage was observed more in low cage density and Hy-line brown hybrids