I'm not positive, but to me it looks like the skin edges are healed, so I think they would have to be trimmed, then sewn together, but that's just a guess.
-Kathy
Excellent links! The duck anatomy picture picture doesn't have the word "crop", but it does show that the esophagus looks looks like the one the left in this picture:
Picture from: http://www.fernbank.edu/Birding/digestion.htm
-Kathy