Heat vegetable oil in a Dutch oven over medium heat; cook and stir chicken pieces until browned, 5 to 10 minutes. Remove chicken with a slotted spoon and place on a plate. Cook and stir onion, green bell pepper, minced garlic, and whole garlic cloves in the same Dutch oven until onion is softened, about 5 minutes.
Return chicken to the onion mixture. Add tomatoes, rice, salt, oregano, black pepper, and bay leaf. Pour in enough chicken stock to cover all the ingredients.
Bake chicken-rice mixture in the preheated oven until rice is tender and chicken is no longer pink in the center and the juices run clear, about 1 hour and 30 minutes. An instant-read thermometer inserted near the bone should read 165 degrees F (74 degrees C).
Stir peas, olives, raisins, and pimento peppers into the chicken-rice mixture. Bake until warmed through, an additional 15 minutes.