Heat oil in a heavy bottom pan. Sprinkle chicken with salt and pepper and brown in hot pan working in batches.
Place all but 3 to 4 lemon slices on bottom of crockpot along with garlic bulbs.
Layer chicken on top of lemon and garlic. Gently pour over stock. Place remaining lemon slices on top of chicken and sprinkle on thyme.
Set slow cooker to low and cook for 6 hours.
When done, remove chicken from pot and strain broth.
Serve chicken and gravy over rice, noodles or creamy grits.