Plymouth Rocks are large, long-lived chickens. Some varieties are good layers while others are bred principally for meat. They possess a long, broad back; a moderately deep, full breast; and yellow skin and legs. The hens have a deep, full abdomen, which is a sign of a good layer. The face of a Plymouth Rock is red with red ear lobes, a bright yellow beak, bay-colored eyes, and a single comb of moderate size. Their feathers are fairly loosely held but not so long as to easily tangle. The chicken's bottom feathers are soft and downy, like baby chicks feathers.

In terms of temperament, both roosters and hens are calm and will get along well with people and other animals such as pets. The hens often will get broody if in the right environment, and are good mothers.