Bone picked up from the last of half a dozen roosters? (6)

I believe the answer is:

coccyx

'bone' is the definition.
(coccyx is a kind of bone)

I cannot understand how the remainder of the clue works.

(Other definitions for coccyx that I've seen before include "End of the human spinal column" , "fused vertebrae" , "bit of backbone" , "Human tail?" , "Tailbone" .)

I've seen this clue in The Guardian.

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