In a food processor, add chicken and process until ground. Work in batches and transfer to a large mixing bowl.
Add egg, onion, garlic and process until chunky puree forms. Transfer to a bowl with ground chicken. Add breadcrumbs, salt and pepper. Using spatula or your hands, mix well.
Form 6 chicken patties, place on a baking sheet and make a divot in each.
Preheat grill on medium-high heat (450-500F) and oil grill grates well with soaked in oil paper towel. Place chicken patties on the grill, cover and cook for 4-5 minutes (grills vary). It is time to flip the burgers when white edges appear and patty is brown on the bottom. Flip carefully only once using good grill spatula and cook for another 4-5 minutes covered.
Serve grilled chicken burgers hot with your favorite toppings and a side salad.
Notes
Store: Refrigerate in an airtight container for up to 5 days. To reheat place burgers in a hot skillet with a splash of water, cover and simmer for about 5 minutes.
Freeze: Cook, cool and freeze leftovers for up to 3 months. Reheat with above directions, will take longer.
Make ahead: Freeze uncooked burgers on a baking sheet lined with parchment paper, then transfer to a large Ziploc bag. Cook from frozen following recipe's instructions + 5 minutes.