Season chicken breasts with salt and arrange in a deep, large skillet. Cover chicken with vegetables. Add bay leaf, thyme sprigs, and chicken stock to the pan. Place over high heat and bring to a boil, covered. Reduce heat to simmer and cook for 15 minutes. Remove bay and thyme sprigs. Remove the chicken breasts and cut into slices. Return chicken slices to the pan and adjust seasoning, to your taste. Put the couscous into a heatproof serving bowl. Ladle 1 1/2 cups of the hot cooking liquid over the couscous, cover and let stand for 5 minutes. Remove the lid, season the couscous with salt, and fluff with a fork. Put a scoop of couscous into a serving bowl, top with chicken chunks and vegetables. Cover meat and vegetables with some broth. Garnish each serving with chives and parsley.
Refrigerate or freeze the whole breast pieces for Portuguese Chicken.