Fowl's crest (4)
I believe the answer is:
comb
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">fowl's crest</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for comb that I've seen before include "Something with teeth (for the hair!)" , "Go over" , "Untangle (hair)" , "Search methodically" , "Groom; search" .)