Pick a Gregorian birth year — the animal and its element are derived from the lunisolar cycle (years switch at Li Chun, the Start of Spring, around Feb 3–5).
People born in a rooster year (the 酉 branch) are often described as precise and articulate — you notice details others gloss over and say what you see. The branch is one of twelve — roughly one-eighth of a full BaZi chart — so treat this as the group backdrop, and your Day Master (the stem of your birth day) as the personal core.
Best pairing by branch: dragon (six-harmony with 酉) Needs patience: rabbit (clash)
Branch compatibility is the coarsest layer. Real compatibility compares two full charts — try the full reading for your own structure.
Is the zodiac animal the same as the year pillar? The animal is the branch (one character) of the year pillar; the pillar also carries a stem with an element, which the calculator above shows.
Why do some "zodiac years" start in February? The lunisolar year begins at the Start of Spring solar term, not Jan 1 — the boundary matters for people born in January or early February.