I believe that about all WDW restaurants went to the chicken added type hot dogs. I e-mailed WDW after reading about the change from all beef hot dogs, to poultry included and did get a reply back. I believe they said one or two places still have all beef hot dogs, but for the life of me, I can't remember which places. I stopped eating hot dogs at WDW, because the chicken added ones, just don't get it for me.
I would guess the frankfurter at Sommerfest at Germany in Epcot is pork and beef without chicken, but I'm not sure.