Arrange chicken thighs in an 8x8-inch glass baking dish. Stir cranberry sauce, curry powder, apple, and raisins together in a bowl; spread over the chicken.
Bake uncovered until sauce is bubbling and thickened, about 35 minutes. Cover dish with foil, reduce oven heat to 300 degrees F (150 degrees C) and return to oven for 30 more minutes. Reduce temperature to 250 degrees F (120 degrees C) and bake until chicken juices run clear and chicken is no longer pink inside, about 30 more minutes. An instant-read meat thermometer inserted into the thickest part of a thigh should read at least 160 degrees F (70 degrees C).
