Young Icelandic Chicken (IMAGE) Uppsala University Caption Young Icelandic chicken with yellow legs. The yellow color is caused by the lack of an enzyme needed to break down carotenoids in the skin. Credit Atli Arnarson Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.