The only time that the shepherds did this was when it was warm enough. In the winter months they would take the herds out during the day and then bring them back in at night and put them in a pen. Therefore , the birth of Jesus could not have been on December 25th but earlier in the year when the shepherds were still letting the sheep stay in the fields over night. Did you ever wonder why God chose shepherds? Of all the people that God could have Chosen why did He choose these shepherds? It is because they chose God! They were humble enough to BELIEVE that there was a messiah coming. No governor, no ruler, no religious leader was told because they didn’t believe.