I'll bow to your superior knowledge - or despair of "science". If the diagnostic bones are missing, I don't know how a pet burial as an example could be excluded.
The most common finds in 'domestic' sites, of such small bones, (ribs, small limbs) are from domestic fowl. Occasionally sommat just doesn't sit well and indicates further investigation.
Bones decay primarily by mineral leaching. This leaves the collagen and that breaks down very quickly. If the soil is mineral rich though, then the leaching process is much slower, but, in very early, i.e. not near full term, or the delivery of an undernourished mother (generally the foetus is a total parasite and will take minerals and the like to the mother's disadvantage) then the mineral structure of the bones is not sound. Almost eggshell like at times. In these circumstances the bones that survive the burial process, *and* the subsequent pressure of the soil on top, are the ones I mention.
I have seen a baby's skull from such a site that was in so many pieces that all I could say was that it was very fragile bone. No teeth, no jaw, the sutures of the skull hadn't closed so all of that had just crumbled to fragments.
The only confusion would be with neonate piglet, and to be honest those would have been disarticulated for consumption. In general we don't seperate the rib cage of a chicken, though it's common to remove the drumsticks and wings. Think of a chickens rib bones, that's the size I'm talking about.
M (who got into it after all
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