Servant goes after farm animal that's run amok (7)
I believe the answer is:
rampage
'run amok' is the definition.
(thesaurus)
'servant goes after farm animal' is the wordplay.
'servant' becomes 'page' (I've seen this before).
'goes after' says to put letters next to each other.
'farm animal' becomes 'ram' (I've seen this before).
'page' put after 'ram' is 'RAMPAGE'.
'that's' is the link.
(Other definitions for rampage that I've seen before include "Rage wildly around" , "Rioting, for example" , "Rush around violently and uncontrollably" , "Frenzy" , "Violent disorder" .)