Heat gas or charcoal grill. In medium bowl, mix egg, turkey, bread crumbs, taco seasoning mix and 1/4 cup of the salsa. Shape mixture into 4 patties, 1/2 inch thick.
When grill is heated, place patties on gas grill over medium heat or on charcoal grill over medium coals; cover grill. Cook 10 to 12 minutes, turning once, until patties are no longer pink in center.
Meanwhile, in medium bowl, mix remaining 3/4 cup salsa and the avocado. To serve, place 1 cup lettuce on each serving plate; top with turkey patty and 1/4 of avocado mixture.