How can we Fool the Rooster?

Written when the clock was set ahead one hour on April 1, 1918.             Our Rooster wakes at half-past five             And crows with all his might,             He tries to wake the people up             Before the day is light.             When Daddy hears the rooster crow             He knows he should awake             And light the kitchen fire, so Ma             Can cook the Johnny cake.             Now, maybe we can fool my Dad             That it's half-past five when it's half-past four,             And maybe the system's the best we have had             To fool some thousands of people or more;             But, how can we fool that rooster?             I have always thought our rooster had             A clock inside of his head,             And I don't know how we can fix it so             We can set the clock ahead.             I asked my Dad, and he said to me,             "Why, son, you surely know             A rooster's instinct wakens him             And tells him when to crow."             Now the hands of the clock we can turn ahead,             We can fool the people and feel content;             But the thing that worries me night and day,             And on which my entire thought is bent             Is, how can we fool that rooster?