Use the tines of a fork to pierce the skin of each bratwurst several times. In a Dutch oven combine bratwursts and apple juice. Bring to boiling; reduce heat. Simmer, covered, about 20 minutes or until bratwursts are no longer pink and juices run clear (160 degrees F); drain.
Meanwhile, in a small saucepan melt apple jelly over low heat. In a medium bowl combine 2 tablespoons of the melted jelly, the sauerkraut, apple pieces, and chile peppers. Set aside remaining melted jelly to brush on bratwursts.
Fold a 30x18-inch piece of heavy foil in half to make a 15x18-inch rectangle. Mound sauerkraut mixture in center of foil. Bring up two opposite edges of foil; seal with a double foil. Fold remaining edges to completely enclose sauerkraut mixture, leaving space for steam to build.
For a charcoal grill, grill bratwursts and foil packet on the rack of an uncovered grill directly over medium coals for 3 to 7 minutes or until bratwursts are brown, turning bratwursts and foil packet once halfway through grilling and brushing bratwursts with the reserved melted jelly during the last 2 minutes of grilling. (For a gas grill, preheat grill. Reduce heat to medium. Place bratwursts and foil packet on grill rack over heat. Cover; grill as directed.)
Serve bratwursts in toasted buns topped with sauerkraut mixture.