Indicates assent and has bales of this sent around to cover sheep, essentially (4)
I believe the answer is:
yeah
'indicates assent and has bales of' is the definition.
I can't tell whether this defines the answer.
'sent around to cover sheep essentially' is the wordplay.
'sent around' becomes 'yah' (I can't justify this - if you can you should believe this answer much more).
'to cover' indicates putting letters inside.
'essentially' indicates the central letters.
The middle of 'sheep' is 'e'.
'yah' enclosing 'e' is 'YEAH'.
'this' acts as a link.
Can you help me to learn more?
(Other definitions for yeah that I've seen before include "Correct" , "Informal agreement" , "positive response?" , "Casual form of yes" , "Definitely (informal)" .)