Burial rituals and nitogen 15 - high status chickens

Burial rituals have been a rich source of evidence for archaeologists, because humans were often buried with artifacts and often with animals too. Cemeteries were also protected from disturbance by building or farming and tended to survive intact for millennia.
Chickens are often found in ancient human graves.

Cockerels have a projection on the tarsometatarsus bone called a spur. Hens do not have this spur. This makes sexing chickens from bone remains quite easy. The spur also grows larger with age.
Excavations from a seventeenth century cemetery in Austria showed that hens were buried with women and cockerels with men. The higher the status of the man, the longer the spur. This shows that older cockerels were buried with higher status men. These birds may have been kept for status and very often would have been used for cock fighting.

All this has been discovered by traditional archeology, but isotope analysis sheds more light on how birds were kept.

We have learned that 13C to 12C ratios from bone collagen show us about how much marine protein was eaten. We have also learned that 15N to 14N ratios tell us about how much high trophic level protein was eaten.

Fig 8.2 shows the remarkable findings of 15N analysis of humans and chickens found buried together. The y-axis shows 15N to 14N ratios. Note: The δ15N notation means that the levels are comparisons of ratios to an international standard.

The correlation between carbon 13 and nitrogen 15 levels in humans and chickens is almost perfect.
"In effect the humans and chickens mirror each other in dietary terms, suggesting that relationships between the two were very close..." Dr Naomi Sykes

High status people would have eaten higher status food (more animal protein) and possibly some of this got eaten or was fed to chickens. This tells us that chickens were closely linked to owners.

Fig. 8.2   Carbon and Nitrogen isotope data for the human and chicken remains from the seventeenth century cemetery, Vienna   at Wien-Csokorgasse  Source: Sykes


1. Can you think of reasons why high status people would have better fed chickens?

2. Would you expect a modern corn fed chicken to have lower or higher nitrogen 15 levels than a chicken living centuries ago?


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Fig. 8.1 X-ray image of a spur on the tarsometatarsus bone of a cockerel (Ohio State University). Hens do not have this spur.