Click the mouse button to make the Chicken jump. Click the retry button when you lose to retry the game. Click the Start button at the beginning of the game to start. Wait to click any button on the lose screen. Do not click the Retry button before the Chicken hits the ground. If you happen to then click the Stop Sign and then click on the Green Flag again. Sorry, but the hills might be separated.
Thanks to @warfame in his YouTube Channel to teach me how to make Flappy Chicken!