Wash the chicken, pat dry. Rub inside with salt and pepper. Stick the opening together with wooden sticks. Tie the legs together with kitchen string. Rub chicken with salt and pepper.
Break apart the garlic bulbs and remove the individual cloves from the stalk. Wash the garlic cloves and let them drain well (do not peel!). Clean and wash the celery and cut into small cubes.
Wash the rosemary and thyme and shake dry. Pluck the thyme leaves from the stems. Heat the oil in a frying pan. Add garlic, celery and herbs and fry briefly while turning. Add the chicken.
First place the breast side briefly in the oil mixture, then turn and cover and braise in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for approx. 2 hours. Remove the lid and braise for another 15 minutes.
Cut the bread into slices. Arrange chicken and garlic cloves in a preheated dish. Press the soft garlic cloves from the skin directly onto the bread.