Heat the olive oil in a large pan on stovetop. Add the chicken thighs to the oil and sauté to a golden brown. Leave chicken in pan and add the onions, garlic, peppers and celery. Sauté mixture for two minutes. Add the rice, chicken stock and saffron into the mixture and bring it to a boil. Finally, add the shrimp, clams, mussels, sausage, sliced lemons, salt and pepper. Cover paella and lower heat. Let simmer for 20- 25 minutes. 

Other Serving suggestions:  add /or substitute catfish, tilapia, pollock, or snapper fillets, mussels or clams for a more hearty meal.