Greek Chicken Soup

Bring broth to a simmer in a medium pot. Meanwhile, beat together egg, water and lemon juice in a heatproof bowl. Whisking constantly, pour half of simmered broth into egg mixture. Slowly pour all of egg mixture into pot (with remaining broth), whisking constantly to prevent curdling. Add chicken, carrots, chives, salt and pepper. Heat soup over very low heat until contents are hot and broth is slightly thickened, stirring constantly.