If there are no cars appearing when you click the green flag, click the green flag again. Use the arrow keys to move the chicken across the roads so she can get to her baby chicks. Dodge the cars and pick up stray chicks on the road. The sidewalk is the "safe" place from cars. There are 3 levels and you get 3 lives.
I got this idea from the chicken crossing the road joke. Thanks to whoever thought of it!