Wayne,
There is no company that I am aware of that does it. I know Macquarie has the facility to do it, but they don't pass onto clients. The way I do it is to simply watch the open interest summary. I use CSI data that has a great summary page of contracts and when the open interest switches you roll. I've only ever been caught twice in my career - last time was actually in Crude in early 2001!
I don't have a specific answer for Hogs although being such an illiquid contract it may be because a few larger players have reason to roll and their activity is enough to impact the OI. I know some US funds use a specific date rather than the formal Notice Day to roll as well, although I highly doubt the larger funds would be playing Hogs. They tend to stick to the financials and currencies nowadays.
Most cash settled contracts, especially the indices, roll the day prior.
Nick