Generously rub the chicken bones with oil, ensuring they are well-coated.

Place the oiled bones on a wire rack set over a baking sheet. This allows for even roasting and better airflow.

Roast the bones in a preheated oven at 425°F (218°C) for 40-50 minutes, until they are well-browned and slightly charred.

Transfer the roasted bones and all the rendered chicken fat from the baking sheet into a large pot or Dutch oven.

Add enough water to cover the bones by about 1 inch. Place the pot on the stove and bring it to a boil.

While the pot is coming to a boil, prepare the vegetables. Roughly chop the celery, carrots, and onion. Leave the skin on the onion for extra flavor and color.

Crush the garlic cloves with the side of your knife to release their flavor.

Add all the prepared vegetables and crushed garlic to the pot with the bones.

Once the stock comes to a full boil, reduce the heat to maintain a gentle simmer. Occasionally skim any foam or impurities from the surface.

Simmer the stock for 90 minutes without herbs to extract flavor from the bones and vegetables.

After 90 minutes, add the fresh thyme, sage, and rosemary to the pot. Continue to simmer for another 30 minutes.

After a total of 2 hours of simmering, carefully strain the stock through a large colander into a bowl to remove all the bones, vegetables, and herbs.

For a much clearer, high-quality stock, perform a second strain. Line a fine-mesh sieve with cheesecloth and pour the stock through it to catch any remaining small particles.

The chicken stock is now ready. It can be used immediately, stored in the refrigerator for 5-7 days, or frozen for up to 3 months.