Violent mama's birched the servants (12)
I believe the answer is:
chambermaids
'the servants' is the definition.
(chambermaid is a kind of servant)
'violent mama's birched' is the wordplay.
'violent' indicates an anagram.
'mamas'+'birched'='mamasbirched'
'mamasbirched' anagrammed gives 'CHAMBERMAIDS'.
(Other definitions for chambermaids that I've seen before include "cleaners" , "servants at home" .)