Amrocks are actually a production version of Plymouth Rocks a.k.a. Barred Rocks. There is also a production version of the Rhode Island Red and a production version of the White Leghorn. Those production versions are used primarily in our agricultural industry and make most of the eggs and meat, besides Cornish.
Amrock chicken. - Page 2
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That´s right. Amrock are also unknown in Great Britain.
In Europe Plymouth Rock come in different colors and are an excellent show birds. They lay about 190 eggs per year (bantam 180) .
Amrock are only known in barred and lay about 220 eggs per year (bantam 190). Amrock and Plymouth differ in shape.
Amrocks are the layers, Plymouth Rock are the "sportive" versions.