Butchers always shut down Halloween night. The skeletons last a bit longer, and the halloween dungeon usually lasts until Thanksgiving or later. I haven't checked to see if the grims are still spawning (they usually do until at least server maintenance on 1 November), because without the butchers for the carving kits, there's little reason.
I personally think that they should last longer - then again, I also think they should bring back the giant turkeys each year, instead of the gimmicky way they now spawn that I've never managed to get them to work.
It's been worst in the past. There were time in the earliest years (10 or more years ago) where they shut down everything at midnight GMT, thoroughly shafting the Western Hemisphere players, as that meant that the halloween stopped DURING the evening of Halloween - Late AFTERNOON for players on Pacific Time, Alaska and Hawaii!