We compared the degrees of stress response of 12 domestic purebred chicken strains that have been bred at National Institute of Animal Science, RDA, Korea since 1980. As a physiological marker of stress response, the expression levels of heat shock protein (HSP)-70, HSP-
, hydroxyl-3-methyl-glutaryl coenzyme A reductase (HMGCR) genes and telomere length were measured by quantitative real-time polymerase chain reaction using the lymphocytes of 1,101 chickens. There was significant difference in HSP-70, HSP-
, HMGCR expression and telomere length among the strains. There was also significant difference in HSP-
, and HMGCR expression between male and female chickens. Different age groups of chicken exhibited different expression levels of HSP-70, HSP-
and telomere length. The results of the HSPs expression level suggested that, the strains of R, L and Y were highly resistant to stress, whereas the strains of S, O and W were susceptible to stress. Although the statistical differences in some of HSPs gene expression existed between genders, the HSP expression results varied in different strains that some opposed to the others, and there might be interaction between strains and genders, which conclude that there was no difference in stress response between male and female chickens. Moreover, despite of significant difference in some of HSPs expression level, it was considered that there was no difference in stress response between ages due to the inconsistent trends among HSP markers.