Figure 1 – The manger, most likely, was made of stone.
Feeding trough for domesticated animals. The Greek term for manger is found only four times in the NT. Three of these instances are in the nativity narrative of Luke and are translated with the English word manger (Lk 2:7, 12, 16). The fourth occurrence, also in Luke’s Gospel, is translated manger in the RSV and NEB, but “stall” in the KJV, NIV, and NASB (13:15).
Elwell, W. A., & Beitzel, B. J. (1988). Manger. In Baker encyclopedia of the Bible (Vol. 2, pp. 1391–1392). Baker Book House.