Hierarchy (7,5)
I believe the answer is:
pecking order
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">hierarchy</span>' is the definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for pecking order that I've seen before include "Animal Farm hierarchy" , "Hierarchy (of hens?)" , "Gradation" .)