Personally, I don't think you need to peel carrots before roasting. The carrots cook for 50 minutes and the skin basically melts into the carrot. So don't waste your time peeling. You do really want to make sure you're cleaning the carrots really well before preparing them, though, because you are eating the skin. If you have some extra time, you can definitely go ahead and peel this if you want. You don't have to, but it doesn't hurt the recipe if you do.