In a large saucepan set over medium-high heat, bring the broth to a boil.
Add the orzo and boil until just tender, about 7 minutes (1 to 2 minutes less than the package directions).
In a large bowl, beat the egg yolks until lightened in color.
Slowly drizzle in 1 cup of the hot broth, whisking vigorously, until egg mixture is hot to the touch.
Add the egg mixture to the saucepan, reduce heat to medium, and cook, whisking occasionally, until thickened to the consistency of heavy cream, about 5 to 7 minutes.
Stir in lemon juice.
Add the chicken and cook for another minute or two until chicken is heated through.
Season with salt and pepper to taste.
