From Wikipedia,

Wooden trough
A manger is a trough or box of carved stone or wood construction used to hold
food for animals (as in a stable). Mangers are mostly used in livestock raising. They are also used to feed wild animals, e.g., in nature reserves. The word comes from the French manger (meaning “to eat”), from Latin manducare (meaning “to chew”).

“And she brought forth her firstborn, a son, and wrapped him in cloths, and laid him in a manger…” Luke 2:7

“This will be a sign to you: you will find a baby wrapped in cloths and lying in a manger…”

Luke 2:12
“So the shepherds hurried off and found Mary and Joseph and the baby, who was lying in a manger…” Luke 2:16
This most beautiful story of the birth of Jesus can be found in the Holy Bible, in the book of Luke, chapter 2, verses 1-20.