Crockpot Chicken with Parsnips and Tarragon

1 large yellow onion
3-4 medium parsnips
4 boneless, skinless chicken breasts
2 tbsp dried tarragon

Cut onion in half, cut halves into wedges. Place in bottom of crockpot. Cut parsnips into thick slices and place on onions. Lay chicken breasts on top. Sprinkle with tarragon. Cook on low for 6-8 hours or high for 4-5 hours.