Try these three:
Bucher Meats, Biglerville PA (right outside Gettysburg):
http://www.manta.com/c/mmzz7mw/bucher-meats - basically a farm with a butcher shop attached. Rough around the edges but popular with the locals.
Wayne Nell & Sons Meats (East Berlin PA, about 30 min north of G'burg):
Home - higher volume than Bucher but still small fries.
Wil-Ar farms (Shippensburg PA) - near Carlisle. Mennonite farm, we get our turkey there. Not sure if they have what you seek but they'll know who does.
If you strike out I know a few farmers around here who raise pigs and may have what you are looking for.