Luke 2:12 NIV reads: "This will be a sign to you: You will find a baby wrapped in cloths and lying in a manger."
But, the King James Version is more familiar: "And this shall be a sign unto you; Ye shall find the babe wrapped in swaddling clothes, lying in a manger."
This shall be a sign. I've always taught, for over 40 years now, that the sign the shepherds would find would be a baby placed in a feeding trough - called a manger. You don't see that kind of bed for a baby every day! So, this would be the sign that they would identify the right baby - the Messiah - a baby born among animals.
But, I've only taught half the truth all these years. You see, the swaddling clothes were just as important, if not more so! The two unique features of the angelic announcement were both signs that the shepherds would recognize. But it was not just a sign to them, but to us as well!