Yes, CHICKENS is a Scrabble word!

Letter values in Scrabble US: C 3, H 4, I 1, C 3, K 5, E 1, N 1, S 1.

Is it a valid word?

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

the flesh of a chicken used for food
a domestic fowl bred for flesh or eggs; believed to have been developed from the red jungle fowl
a person who lacks confidence, is irresolute and wishy-washy
a foolhardy competition; a dangerous activity that is continued until one competitor becomes afraid and stops

Also: gallus gallus.

Not playable in Scrabble US: POULET, VOLAILLE.