As a kid I often wondered why the shepherds were invited by the angels to go visit the newly born Jesus.
In the area around Bethlehem the sheep were bred for the purpose of sacrifice in the Temple. Every first born lamb born on these hills under the care of the shepherds were checked for blemish and set apart for the purpose of sacrificial death.
Luke 2:8 says "in that same region' meaning that these Shepherds were in the same region as Bethlehem.
So these shepherds who had the responsibility of witnessing and setting apart the first born male lambs that were born, were invited to witness the birth of THE LAMB OF GOD.
It's a beautiful touch to Christ's birth.