Grooms may see horses eating mints initially (5)
I believe the answer is:
combs
'grooms' is the definition.
(combing is a kind of grooming)
'horses eating mints initially' is the wordplay.
'horses' becomes 'cobs' (cob is a kind of horse).
'eating' indicates putting letters inside.
'initially' says to take the initial letters.
The initial letter of 'mints' is 'm'.
'cobs' placed around 'm' is 'COMBS'.
'may see' acts as a link.
(Other definitions for combs that I've seen before include "Crests" , "Searches thoroughly" .)