Yes, BARKERS is a Scrabble word!

Letter values in Scrabble US: B 3, A 1, R 1, K 5, E 1, R 1, S 1.

Is it a valid word?

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

someone who stands in front of a show (as at a carnival) and gives a loud colorful sales talk to potential customers
informal terms for dogs

Also: bow-wow.