In Zoroastrianism, Ahura Mazda (the supreme god) was sometimes depicted as a man with the head of a rooster. Perhaps your bead is based upon this idea.
However, I am not confident this is an ancient bead.
This link presents some interesting ideas related to Persian animal symbols, and demonstrates the importance of roosters in symbology:
https://zoroastriansnet.files.wordpress.com/2008/11/birds-animals-and-symbols-in-zoroastrianism.pdf
JDA.
I wasn't expecting an answer to my question anymore.
My mind is going in the same direction: could it be Abraxas?