In the days of the first century, most everything was made out of stone. It was the most common and available resource with which to build. Wood was much more scarce and was either used sparingly or imported. Mangers were used by families and communities to feed and water livestock.
The manger that Jesus was placed in just after his birth was likely made out of stone rather than wood [Luke 2:7-16].
This photograph of a manger was taken in Korazim, Israel just after a rain shower.