I'm putting my old stalking kit back into service and thought it might be worthwhile mentioning this item - if it's already been posted just ignore me and I'll get back under my rock.
Now that it's getting a bit chilly while sitting around - as I discovered this morning - it's probably time to get into this sleeping bag if up in a high seat, in a hide or just lying prone waiting for deer to appear.
I've had years of use out of my one, which cost me about £20. As you can see, you can wear it like a jacket and there is a zipped opening in both the waterproof outer and quilted inner at about knee height, so you can get your legs out and walk around or climb a high seat while already 'wearing' it - the lower foot section folds up behind and is secured around your waist by an attached strap. Undo the strap when in position and it reverts back into a full bag to keep your tootsies warm.
The quilted inner is not too thick nor bulky, so walking to your preferred ambush point already kitted up is no great problem. I've really found it a great piece of kit and it's kept me warm and ready for action over the years. Available from a number of sources - just google german army sleeping bag or something similar.