Meat Thermometer & Crock Pot?

I have a basic meat thermometer (plain old dial kind - not digital). I am going to cook my first WHOLE chicken in a crock pot and I want to make sure that it reaches the proper temperature & that I don't pull it out raw. Can I put the thermometer in before cooking and leave it there the whole time like I would for oven cooking or should I open the lid and quick check it close to the end?