The calm hen gets agitated in an English town (10)
I believe the answer is:
cheltenham
'an english town' is the definition.
'cheltenham' can be an answer for 'town' (town in Gloucestershire). I am not sure about the 'an english' bit.
'the calm hen gets agitated' is the wordplay.
'gets agitated' indicates anagramming the letters.
'the'+'calm'+'hen'='thecalmhen'
'thecalmhen' anagrammed gives 'CHELTENHAM'.
'in' acts as a link.
Can you help me to learn more?
(Other definitions for cheltenham that I've seen before include "Gloucestershire racecourse" , "GCHQ location" , "English racecourse and spa town" , "West Country spa town with racecourse" , "Gloucestershire town" .)