Hunting in freezing conditions almost certainly means freezing feet, and that makes it a literal pain to get around.
Thermacell Heated Insoles might be able to help out, though.
Unlike heated boots, Thermacell's insoles can be recharged over and over, and can fit in most footwear. If it doesn't fit, no problem: The insoles can be trimmed to fit any shoe or boot.
Thermacell Heated Insoles are operated remotely, allowing users to choose between high and medium heat, or no heat at all.
With a battery life up to 500 cycles, the insoles can be recharged after every use and should last the user for years.
Thermacell Heated Insoles are available at Bass Pro Shops.