The pictures aren't the best, but my excuse is that they were taken from a vehicle. That said, the top photo shows the silvery wing tips of the black vulture and the bottom photo shows the silvery bar of the turkey vulture.
The vultures were enjoying a freshly manured field. Not sure if they were actually eating anything. Perhaps the lovely aroma drew in the turkey vultures and the sight of all the turkey vultures drew in the black vultures. Treebeard says maybe they were just happy that it was a nice day ;)