Yes, OSTRICHES is a Scrabble word!

Letter values in Scrabble US: O 1, S 1, T 1, R 1, I 1, C 3, H 4, E 1, S 1.

Is it a valid word?

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

a person who refuses to face reality or recognize the truth (a reference to the popular notion that the ostrich hides from danger by burying its head in the sand)
fast-running African flightless bird with two-toed feet; largest living bird

Also: struthio camelus.