In a large bowl, combine the ground chicken, panko breadcrumbs, beaten egg, chopped onion, minced garlic, Worcestershire sauce, dried thyme, salt, and pepper. Use your hands to thoroughly blend all the ingredients until they are mixed well.

Divide the mixture into 4 equal portions and shape each portion into a patty about 1/2-inch thick. Make a slight indentation in the center of each patty to prevent it from puffing up during cooking.

Preheat a grill over medium high heat and oil the grill grates so that the patties don't stick to the grill.

Add the chicken patties to the grill on direct heat and cook for about 5 minutes on each side, or until they are browned and cooked through. The internal temperature should reach 165°F.

Remove the patties from the grill and let them rest on a plate for a couple of minutes.

Toast the hamburger buns lightly on the grill.

Assemble the burgers by placing a chicken patty on the bottom half of each bun, and topping it with your choice of lettuce, tomato, red onion, pickles, mustard, and/or mayonnaise. Place the top half of the bun on the burger and serve immediately.