Yes, FITCHES is a Scrabble word!

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

Is it a valid word?

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

dark brown mustelid of woodlands of Eurasia that gives off an unpleasant odor when threatened

Also: mustela putorius.

Not playable in Scrabble US: FOULMART, FOUMART.