When the Araucana was first introduced to breeders worldwide in the mid-20th century, the genetics that produced tufts were recognized to also cause chick mortality Two copies of the gene cause nearly 100% mortality shortly before hatching. The tufted gene is dominant, however. Because no living Araucana possesses two copies of the tufted gene, breeding any two tufted birds leads to half of the resulting brood being tufted with one copy of the gene, a quarter being clean-faced with no copy of the gene, and a quarter of the brood dead in the shell, having received two copies of the gene.
In the decades to follow, most breeders took one of two tacks—either to preserve the old style of bird, or to breed out the tufts while increasing productivity.
In 1976, the first standards for the breed were accepted by the APA, conforming to the traditional style. This was followed, in 1984, by a second standard for the "improved" variety.
Approximate weight
| Rooster | 2.7–3.2 kg | 6–7 lbs |
| Hen | 2.3–2.7 kg | 5–6 lbs |
| Rooster | 740–850 g | 1.6–1.87 lbs | |
| Hen | 680–790 g | 1.5–1.75 lbs |
This is a Plymouth Rock hen, she is beautiful, and adorable. Plymouth Rock chickens are a popular type of breed, and are very friendly. They are layers of brown eggs. They are great mothers. I have a pet hen that is a Plymouth Rock that looks like the hen in the picture above, she is very tame and beautiful.