Here is the full list of all 15 Why Chicken Why achievements.
Poor little guy Be Careful.
Time to get crackin'.
Enter 1st secret level.
He really hates exercise.
You saved the rogue baby chicken from the frog.
You picked up an extra life.
You froze yourself.
You burned the chicken.
Obtained the rock hammer.
You have beaten the game once.
You lost all your chicken lives.
Enter 2nd Secret Level!
The poison frog warped you!
Step on a floating rock.
You beat the game & restarted.