Do you suppose that if Tyson sold the plants instead of closing them that someone else might run them more efficiently than they did.
Trucking the extra distance to the new plant isn't free. Anybody operating the old plants would have the trucking advantage over Tyson.
One reason Tyson could close those plants and expand the other is that there is nobody else in the old location to kill the cattle there. If there were they would not be guaranteed to get them for the expanded plant.
When there is no competition in the region, decisions are made differently than if there were.