Identifying Chicken Breeds in the Archaeological Record: A Geometric and Linear Morphometric Approach

Domestic fowl remains are a small but significant element of many post-Iron Age bone assemblages, reflecting the importance of the many roles of this species, whether in augury, entertainment or different aspects of food-production. Size and shape variation in archaeological chicken bones has long been recognised as a possible indicator of different breeds or types associated with these roles, implying selection for favourable characteristics and the development of specialisation in poultry-keeping. This study investigates the potential of shape-analysis for identifying bone shape variation that may characterise particular morphotypes, helping to elucidate the processes of domestication and selection and the means and motivations behind breed development. The thesis explores the potential for geometric morphometrics to complement traditional biometrical analysis in identifying osteological differences in domestic fowl remains. By focusing on shape independent of size, GMM offers a new approach, identifying subtle variations in bone morphology which would not otherwise be detected. GMM techniques were applied to selected post-cranial bone elements from modern domestic fowl of known-breed, age and sex, revealing consistent morphological similarities and differences in some breeds. These methods were then applied to archaeological elements from Romano-British, Anglo-Saxon and Early Modern deposits, with the aim of identifying progressive breed development within this wide chronology. Analysis of linear metrical data from the same modern and archaeological material enabled comparisons to be made between the two techniques. The findings support the use of both measurement ratios and GMM methods for determining breed-related variation in selected chicken elements and suggest a strong potential for extending the research using additional bone elements and 3D imaging techniques.