Expanded part of the oesophagus in birds in which food is stored before passing on to the gizzard (4)
I believe the answer is:
crop
(Other definitions for crop that I've seen before include "Produce - short hairstyle" , "Harvest - short hairstyle - whip" , "Trim (a photograph)" , "The handle of a whip, or part of bird's neck" , "Short cut - taken when hunting?" .)