Malondialdehyde values in both plasma and yolk were increased in high stocking density-challenged hens. On the other hand, dietary supplementation with CrMet and vitamin C decreased plasma MDA content. There were interactions between stocking density and supplemental Cr and/or vitamin C for yolk MDA contents, so that dietary CrMet and vitamin C supplementation had more reducing effect on MDA values in high stocking density-challenged hens