Do you have a heating element for their water? I use a concrete birdbath top and a small round heater that sits at the bottom. Keeps the water from freezing ever at -20
What about water if no outlets? I’m scared to use hot hands as there are no burn units for cats
Is there some way to insulate around the outside of the water dish? You want to minimize heat loss by reducing the surface area exposed to the cold. If you had a hollow plastic dish, you could place the hot hands beneath it to better contain the heat and keep it away from the cats at the same time. By the way, they don't get that hot- I had them inside my gloves while shovelling snow today, and no burns on me..
. And especially not if put on the bottom or sides of of a water dish. I think there are insulated dishes that will keep it unfrozen overnight if you put warm water in. Anyway if you can't do that they'll still be fine as long as you offer water at least 3 times a day.
However cats can tear the packets apart which are toxic.
I hate to think so but it sure seems that way. Goes along with the mind set 'I got mine and the heck witheveryone else'
Not how I was brought up 
Around here unless you have a 'No Trespassing' sign in place the Police legally can't do anything.
Not like "a drop of poison" toxic. They can cause iron toxicity if enough of it is eaten. I really don't think cats will eat enough to be harmful (if any); they won't snork them down like dogs might. I can't find any cases of cats eating them anyway. There are case studies for dogs and elderly people but not cats.
That looks cool. I wish I didn't have limited mobility or I would do the same. I don't even have old pieces of furniture to use although that would definitely be an improvement on what I do have.
I bought some of these last year. It may be tricky to use outside because they lose their warmth when a cat is not laying on them. They never seemed to stay warm, but then I tried them under the covers with me near my feet and they would still be warm when I woke up. And once the kitties figured them out, too, with them laying on them more they stayed warm for longer.
What about the usb rechargeable hand warmers? I haven't tried them outside but what if I get a small styrofoam box (I have pieces to make some with and put the rechargeable hand warmers in. At least for the night time. During the day I'm up and can run in and out with fresh water if needed. I have two that I bought for myself that I most likely won't need at the moment. Even if I trusted the hot hands they are expensive as only a one time use
Thanks. I'll test it out here and see how it will work or at what point the plastic bag melts. There are 3 settings to the hand warmers and the hottest can be hot but may not be so hot outside. I'll get going on that today.
