Divide the chickens into joints, and season well with salt and pepper. Melt the butter in a saucepan and, when hot, put in the pieces of chicken and cook till a golden brown on all sides. Slice the onions, add to the chicken and brown lightly. Then sprinkle with the flour, mix well and cook till the flour browns. Now put in the sliced tomatoes, the chopped garlic and herbs, and the sliced pimientos, and simmer gently with die lid on for 20 minutes. Then add the hot stock or water, season highly with salt and pepper, and simmer gently for 45 minutes. To serve, put the pieces of chicken on a hot dish and pour the sauce over them. Boiled rice is served with this.