This experiment investigated the physiological and behavioral responses of Greylag geese (Anser anser) fed different fiber sources when exposed to the common stressors at harvest, primarily involving the procedures of fasting, transport, catching, etc. A total of 240 4-week-old Greylag geese were allocated to 4 diets with different fiber sources (corn straw silage [CSS], steam-exploded corn straw [SECS], steam-exploded wheat straw [SEWS], and steam-exploded rice straw [SERS]). The birds were fed for 12 wk and harvested at 16 wk for slaughter. Blood samples designated to determine stress status were collected before (pre-stress) and after (post-stress) the harvest procedure was carried out. Irrespective of the dietary differences, the harvest procedure caused the concentration of superoxide dismutase (SOD) to drop (P < 0.01) 13.57% and increased (P < 0.01) that of creatine kinase (CK) by 186.21% (post-stress vs. pre-stress), inferring that the birds had experienced a severe stress. As to the dietary effects, the birds fed alternative fiber sources did not develop dissimilar (P > 0.05) pre-stress blood parameters and behavioral sensitivities, while the birds fed CSS had a higher (P < 0.05) post-stress concentration of methane dicarboxylic aldehyde (MDA) than those offered SECS by 22.01%, suggesting that feeding Greylag geese alternative fiber sources influenced their stress response.