If the "meat" is truly unrotting, and as big as you describe, I think there'd be a whole supply chain and it might look a lot like stonecutting. You would have butchers/miners/stonecutters "quarrying" the meat into blocks or cubes, perhaps salting them for preservation, and loading them onto wagons. Wagons would carry the meat to markets or to seaports to ship them around the world.
I am trying to imagine how the meat could be "unrotting" and my assumption is that it might be frozen. You can actually eat long-frozen mammoth meat found in the permafrost in Siberia. Therefore, after "quarrying" the meat it makes sense that they might have to add a preservative (such as salt); also that makes it seem less magical and more realistic.
This is something akin to the medieval/renaissance salt cod trade. Europeans would sail as far as Maine to harvest Atlantic cod, salt and dry the meat on the shore, and then ship it back to Europe for sale. So, a long supply chain is economically feasible if the meat is abundant and the technology for preserving it is available.