In meat-type poultry breeding, pectoral angle (PA) is a conventional anatomical indicator for changes in body conformation and meat traits; its correlation to egg performance is however deemed controversial. In this context, we revisited, assessed and put forward evidence for the usefulness of this classic phenotypic variable and its specific integrative index of pectoral angle-to-body weight ratio (PA/BW). Specifically, we identified respective correlations and used them for distinguishing the major categories (production types) of diverse chicken breeds under the traditional classification model (TCM) and genotypic clustering models of the global chicken gene pool subdivision. Also, the usefulness of the supplementary integrative egg mass yield index (EMY) for this objective was demonstrated. Because of estimating the total mass of eggs laid (i.e. egg number times egg weight), EMY can serve as an indicator of egg production. Direct approximation of EMY values by PA and BW values did not lead to significant correlation dependences between these indicators in each of the four breed utility types according to TCM. However, using the ratio of PA to BW, instead of PA and BW alone, resulted in significant correlation of EMY with PA/BW, allowing for distinction between egg-type and non-productive breeds. The validity of the proposed correlation-based models was supported by PCA and Neighbor Joining clustering analyses. Collectively, we suggested that PA can be a potentially correlated trait for selecting hens and roosters in breeding flocks to boost egg yield. These results can also be applied to chicken breeding as well as conservation- and phenome-related research.

The San Diego Presidio, established in AD 1769, was the first European settlement in Upper California. Very little is known about chicken husbandry in colonial America, which makes this study the first comprehensive analysis of chicken remains in North America. Chickens are scarcely mentioned in historical accounts describing early California, and information on their sex, age, or management is rare. The faunal assemblage from the San Diego Presidio yielded 20 avian and 14 mammalian species. Chicken remains were studied through a wide range of zooarchaeological methods, including taphonomy, biometry, medullary bone, epiphyseal fusion, butchering, and body-part representation. Taphonomic analysis indicates good preservation of the bone assemblage. The biometric study points to two breeds of chickens: a smaller (bantam) breed alongside a standard-size chicken. The percentage of juvenile chickens (23%), the rooster/hen ratio (1:8.5), and high proportion of medullary bone point to on-site chicken husbandry focusing on meat and egg production. The historical record suggests that California presidios were not self-sufficient and that they relied on food provisioned from Mexico and nearby missions. We argue that small-scale poultry production, likely managed by women and children, provided California presidios with a form of subsistence independence.