Luke 15:5

“And when he has found it, he lays it on his shoulders, rejoicing.”

Note that in this narrating of the parable success is assumed. It is not ‘if' He finds it, but ‘when' He finds it (contrast Matthew 18:13, which demonstrates that the parable there was given on a different occasion. The emphasis of the parable would vary depending on the emphasis Jesus wished to lay). This carrying of the sheep on his shoulders would be normal practise for a shepherd. The sheep would be exhausted, and the shepherd triumphant and rejoicing (compare Isaiah 40:11).