Yes, HOATZIN is a Scrabble word!

Letter values in Scrabble US: H 4, O 1, A 1, T 1, Z 10, I 1, N 1.

Is it a valid word?

HOATZIN is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

crested ill-smelling South American bird whose young have claws on the first and second digits of the wings

Also: opisthocomus hoazin.

Not playable in Scrabble US: STINKBIRD.