Daydreaming? Shearers may be doing it (13)
I believe the answer is:
woolgathering
'daydreaming?' is the definition.
('woolgather' can be a synonym of 'daydream')
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for woolgathering that I've seen before include "may be dreamy" , "Absent-mindedness" , "Daydreaming" .)