When I go shop for turkey meat, it's usually sliced by the same machine that also is used to cut pork. Is this turkey Halal or Haram?

Praise be to Allah, the Lord of the World; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.

If the machine that slices pork meat is not cleaned and purified after its use then any meat that is chopped after that is impure and it is not legal to eat it.
So, you should ask the owner of this shop to purify the utensil he uses to slice pork before he uses it to slice Halal meat. These utensils include the knife, the receptacles, the scale, if the meat is not dry, as well as the slicing machine.
The evidence for this is the Hadith that is reported by al-Bukhari , Muslim and others that Thalaba al-Khashani said: "Messenger of Allah (peace be upon him), we travel about and when we come to Jews, Christians and Magians we can obtain nothing but their vessels." He replied, "If you can obtain nothing else, wash them with water and then eat and drink out of them" .
Abu Dawood 's another version says: "And they cook pork in their pots and drink alcohol from their utensils" .
Allah knows best.