Add the carrots, avocado leaves, oregano and remaining salt to the slow cooker. The liquid level should be just below the thighs’ surface. If needed, add more beer, chicken stock or water to achieve the desired volume of cooking liquid. Turn the slow cooker on, setting for 4 hours on high, or 6 hours on low. Cover with the lid, and allow to simmer/braise.
This can also be done in a sealed Dutch oven at 300°F/149°C for 2 hours.