Colony of rabbits (6)
I believe the answer is:
warren
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">colony of rabbits</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for warren that I've seen before include "Area of rabbit burrows" , "densely populated area" , "In Hastings, for example," , "Network of caves as built by rabbits" , "Maze of passages" .)