This is the chicken's wing with the area to be cut shaded in blue.
One of the challenges of keeping chickens in the city and letting them roam about your yard is preventing them from taking a short fly over your fence. We have had our chickens for a while and our white chicken, Lucky, finally decided to take a leap. She was gone for over 24 hours but came back to our gate. Needless to say, we decided it was in her best interest to have her wings clipped to prevent her from flying away in to dangerous territory.