In a large saucepan, season the stock with salt and pepper and bring to a simmer. Transfer 1 cup of the hot stock to a blender. Add 1/2 cup of the rice, the egg yolks and the lemon juice and puree until smooth. Stir the puree into the simmering stock along with the chicken and the remaining 1 1/2 cups of rice and simmer until thickened slightly, 10 minutes. Stir in the dill and serve.