If you have to sit still, try flexing your toes and stretching your fingers. Hang them straight and low, allowing warm blood to circulate.
Mittens are best for sitting still, your heart beat will warm your fingers when you have game in sight to shoot.
Black "Mickey's" are for cold wet, and white "Mickeys" are for dry cold, which is usually below Zero.
Wear loos, fluffy socks that fill in the boot with out being tight.
Arctic trick;Seal oil......maby olive oil for you , slather'd on a salad? Both are good for cleaning out your veins, and are redily absorbed for immediate use by the body.
Eat properly befor hunting. Snack often.Take Candy, it will warm you.
Take sweet tea to drink in your thermos.Hold the thermos! Itll be warm, and we often pack them in an insulating bag to keep them warm longer.That should really help, and its quiet...LOL!
We eat Seal Oil with frozen, cooked, dryed meat , cut veggies, roots, berries, dry'd fish and blubber chunks for the immediate Calories it gives.
Actally, oldtimers travled with a pich of salt and a supply of Seal Oil, as it will caloricly make frozen meat worth eating, warming you rather than chilling you, and you dont need a fire to get warm.
Chemical heaters are fine, just make sure they "Breath" for a bit, and heat up. I once put a set immediatly in my boots, and sufferd, untilll the next day, when we got to a village and I took off my boots...then they got Oxygen and warmed...
PMO!!!! LOL, live and learn!
Good luck!