Red Rock chicken, the only chicken still popular to any large extent in the United States today for both meat and eggs. It resulted from a cross between a Rhode Island Red male and a Plymouth Rock female. The breed recently acquired new value when it was discovered that the sex of the day-old chicks could be determined by the differences in the color of their down. The variety is raised primarily in New England.
The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia University Press. All rights reserved.