Rub the chicken with thyme and a pinch each of salt and pepper. Cook the bacon in a large skillet over medium heat until crisp, about 5 minutes. Remove the bacon and reserve for later.
To the skillet, add the chicken and sear until golden brown on both sides, about 3 minutes per side. Remove the chicken from the skillet. To the same skillet, add the onion, cook 5 minutes, then remove from the heat and place in the slow cooker. Add the garlic, carrots, mushrooms, tomato paste, red wine, broth, and bay leaves. Season with salt and pepper. Stir to combine. Add the chicken, skin side facing up.
Slice the top portion of the garlic head off. Poke holes in the potatoes using a fork and place on top of the chicken. Arrange the thyme sprigs and garlic around the potatoes. Cover and cook on low for 5-6 hours or on high for 3-4 hours.
During the last 30 minutes of cooking, remove the lid and Continue cooking the chicken with the lid off to thicken the sauce slightly.
Sprinkle with bacon. Remove bay leaf and thyme stems. Serve in large bowls family style with biscuits.