Put the chicken sausage in a frying pan with a teaspoon of olive oil and cook over medium heat until browned. Drain on a paper towel lined plate, then slice into coins.
Place the olive oil, chopped onion, celery, lentils, potatoes, chicken sausages, broth, and spices in the slow cooker. Cook for 4 hours on high, or 6-8 hours on low, until lentils are tender.
Five minutes before serving, stir in the kale and place the lid back on the slow cooker.