Have you ever un-friended coworkers en masse on Facebook?

I have my immediate supervisor as a FB-friend (added during a period I was laid off) so as you can imagine this encourages a degree of serious self-censorship when I post anything and I am getting tired of it. I am considering referring all current and past co-workers I don’t consider real personal friends to my LinkedIn profile and dropping them on Facebook. Has anybody out there done this? Any advice on how to break this news to them to avoid any hurt feelings?