In the European Union, legislation concerning animal housing is becomingstricter because of animal welfare concerns. Feather pecking (FP) in large grouphousing systems is a major problem. It has been suggested that corticosterone(CORT) response to manual restraint as a measure for stress is associated withFP behavior. The aim of the current study was to identify QTL involved in FPbehavior and stress response in laying hens. An F2 population of 630 hens wasestablished from a cross between two commercial lines of laying hens differingin their propensity to feather peck. The behavioral traits, measured at 6 and 30wk of age, were gentle FP, severe FP, and aggressive pecking. Toe pecking wasmeasured at 30 wk of age and CORT response to manual restraint was measured at32 wk. All animals were genotyped for 180 microsatellite markers. A QTL analysiswas performed using a regression interval mapping method. At 6 wk of age, asuggestive QTL on GGA10 was detected for gentle FP. At 30 wk of age, suggestiveQTL were detected on GGA1 and GGA2 for gentle FP. A significant QTL was detectedon GGA2 for severe FP. At 32 wk of age, a suggestive QTL was detected on GGA18for CORT response to manual restraint. In addition, a suggestive QTL wasdetected on GGA5 with possible maternal parent-of-origin effect for CORTresponse.