In a medium saucepan combine rice and 4 cups chicken stock. Bring to a boil, reduce the heat and simmer until all the stock is absorbed into the rice, about 20 minutes.
Meanwhile, heat oil in a heavy-bottomed sauté pan over medium-high heat. In a large nonstick skillet, cook sausage 10-12 minutes, until browned. Once browned, take out sausage and cut into slices; place sausage back into sauté pan.
Add garlic, onion, celery, and green bell pepper. Cook until softened, about 5 minutes. Season with salt and pepper.
Add 1 cup chicken stock and cayenne. Cook until stock has reduced a little.
Add cooked rice and parsley and stir thoroughly. Taste and season with salt and pepper, if necessary.