Rabbit colony (6)
I believe the answer is:
warren
'rabbit colony' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for warren that I've seen before include "Film star Beatty is down with the rabbits" , "Where fast-breeders are at home" , "Network of caves as built by rabbits" , "Rabbit burrow" , "Network of tunnels created by rabbits" .)