I am a hobby breeder and I need to ship a gecko to the chicago area the temp there is around 32F. I was wondering if it would be safe to ship or should I wait for warmer weather. I am using a styro-cooler box inside a regular cardboard box. The heat pack (uniheat 40-hour) I was planning to ship USPS express. I was also wondering if anyone has a breakdown on when to use additional heat packs. I have found that in mild temp (65F) the heat pack effectively heats up the box to around 10-13F higher. Should I punch holes in the cardboard box and styro or just the styro or neither? Should I use two heat packs. What temps should I expect my package to be exposed to?