Barred Plymouth Rocks are one of America’s oldest and most popular breeds (1869). They are an excellent dual purpose breed, known for their efficient production of large brown eggs. They are good winter layers, cold hardy, heat hardy, and are moderate foragers. All of their plumage is black and white barred which is the result of the barred (B) gene. Because males are homozygous for the allele (BB) they are therefore lighter.