In 4- to 5-quart Dutch oven, heat oil over medium heat. Add chicken pieces; cook about 5 minutes on each side or until browned (if necessary, cook chicken a few pieces at a time). Remove chicken from Dutch oven; set aside.
In same Dutch oven, cook onion and bell pepper 3 to 4 minutes, stirring occasionally, until onion begins to brown; drain. Stir in tomatoes, garlic, curry powder, thyme, salt, ground red pepper and broth. Return chicken pieces to Dutch oven. Reduce heat to low; cover and simmer 30 to 40 minutes or until juice of chicken is clear when thickest piece is cut to bone (180°F).
In 2-quart saucepan, heat water to boiling. Stir in couscous. Remove from heat; cover and let stand 5 minutes.
Stir apple into chicken mixture; simmer uncovered 2 minutes longer or until apple is hot. Fluff couscous lightly with fork before serving with chicken mixture.