Chicken Adobo With Chicken Livers

Name: Chicken Adobo With Chicken Livers
Ingredients: 2 tbsp. vegetable oil; 1 tbsp. annatto seeds; 3 lb. whole chicken legs, separated into drumsticks and thighs; 4 cups distilled white vinegar; 1 tbsp. kosher salt, plus more; 2 tsp. whole black peppercorns; 3 bay leaves; 6 garlic cloves, thinly sliced; 1 large yellow onion, halved and cut lengthwise into 1/2-inch-thick slices; 1 lb. chicken livers, rinsed and dried