I started to cook chicken casserole in the slow cooker, for about 20 minutes on high so that I could then turn it down to low and leave cooking. However, I accidently turned the slow cooker off and so the chicken has been left to cool and had been sitting there for 5 hours.  Can I now continue to cook this casserole in the oven? 
Chicken which is essentially still raw should not be left out for 5 hours at room temperature. I doubt it's safe to eat anymore.  