Golfers who struggle with a chicken wing often avoid using the shoulder correctly and bend the elbow instead. Training some slow-motion follow-through movements can help you feel what it's like to keep the left arm straight into the follow-through. You may also experience more body rotation in order to keep the lead arm straight. At first, this movement can feel "stiff" but with some practice it will feel more stable, connected, and controlled. This likely helps with better ground contact and face control for golfers who battle the chicken wing.