Leave it to Jerome:

Jesus Was Born in a Stable of Dung. Jerome: He found no room in the Holy of Holies that shone with gold, precious stones, pure silk and silver. He is not born in the midst of gold and riches, but in the midst of dung, in a stable where our sins were filthier than the dung. He is born on a dunghill in order to lift up those who come from it: “From the dunghill he lifts up the poor.” On the Nativity of the Lord. (Just, A. A. (2005). Vol. 3: Luke. Ancient Christian Commentary on Scripture NT 3. (39). Downers Grove, Ill.: InterVarsity Press.)