Place 1 chicken breast between 2 pieces of plastic wrap or waxed paper. Working from center, gently pound chicken with flat side of meat mallet or rolling pin until about 1/4 inch thick; remove wrap. Repeat with remaining chicken breasts.
In shallow bowl, mix flour, salt and pepper. Coat chicken breasts with flour mixture. In 10-inch skillet, heat oil over medium-high heat until hot. Add chicken; cook 3 to 5 minutes on each side or until golden brown on outside and no longer pink in center.
Remove chicken from skillet; cover to keep warm. Add broth, Worcestershire sauce and marjoram to skillet; cook and stir 1 to 2 minutes or until hot. Stir in lemon juice and parsley. Serve over chicken.