People moving, and people opposing, keeping bats caged (6)
I believe the answer is:
nomads
'people moving' is the definition.
(nomads roam around)
'people opposing keeping bats caged' is the wordplay.
I cannot quite understand how this works, but
'bats' could be 'mad' (bats can informally mean mad) and 'mad' is found within the answer.
'people opposing' could be 'nos' (eg people voting no) and 'nos' is found in the leftover letters.
No letters remain.
This explanation may well be incorrect...
'and' acts as a link.
(Other definitions for nomads that I've seen before include "Damson for wanderers" , "They wander" , "Damson for wandering tribes" , "They travel all year round" , "Gypsies" .)