Hello OwlThatLikesAnts;
The heat pack is an option that they add to the order form when the weather is, or threatens to be, below freezing during the delivery time. The discrepancy in the date is probably because they can never be sure when that freezing weather will happen. I've purchased the heat pack in winter and the ants have arrived in good condition each time. In fact, in one instance the ants were shipped just before a terrible winter storm that closed roads for days and I figured my ants would arrive dead for sure. It took two weeks for them to be delivered. Amazingly the heat pack did its job and the ants were fine. If the heat pack is available on the order form, I would get it, it's cheap insurance if freezing weather is a concern. I should also give credit to our very understanding postman who delivers my ants to the door, into my hands, when the weather is freezing, instead of leaving them in the post box at the road.
There is a chat function on the Canada Ant Colony website, I've asked questions there and received answers the next day. You can also email Teddy at Canada Ant Colony and ask specific questions about your order.
RPT
My father always said I had ants in my pants.