I have personally caught a good mess of brim on various trips in the winter. I rarely target brim in the winter, but on those trips I have done well.

I find them in deep water around cover. If I go it is usually for shellcracker and brim, and before the end of the day I have a right good mess of both or either of the two.

By the way I've never seen a "sluggish" brim...they always try to pull me out of the boat...even in the winter.

Happy Fish'n