Yes and no. Chicken can cook in a slow cooker for 6-8 though the longer it cooks, the meat is more likely to slide off the bone. Just be sure that there is plenty of liquid so it doesn't dry out. I don't recommend cooking it for longer, especially if you aren't there to keep an eye on it as it may overcook. It's important the chicken doesn't sit for a long period of time after the crockpot is turned off. When not kept hot, chicken is more likely to be exposed to unsafe conditions.