Are non-Christians also sheep?

Are non-Christians also sheep? In the context of the parable of the lost sheep (Luke 15:1-32) those who are sinners are like lost sheep. The term sinner was derisively used by super-religious Pharisees and teachers of the law. Jesus taught that even the most pious believers have done wrong, because all human beings have sinned. How dangerous and irresponsible it seems for a sheep farmer to leave 99 alone and unprotected for the sake of one lost sheep. The math simply doesn't add up. Locally, lambs average about $350 a head. At those prices, 99 would cost almost $35,000. Putting $35,000 at risk to save $350 does not make business sense, but it does make heavenly sense. The exaggeration shows how much God cares for the lost and his heart’s desire for them to join his flock.