In a large bowl, combine ground chicken, breadcrumbs, egg, salt, and pepper. Mix well until all ingredients are evenly distributed.

Divide the mixture into four equal parts and shape each into a patty about 1/2 inch thick.

Preheat the grill or skillet over medium-high heat and brush with olive oil.

Cook the patties for about 5 minutes on each side or until the internal temperature reaches 165°F and the juices run clear.

Serve the burgers on buns with lettuce, tomato, and onion slices.