I have seen them. tried them, and know of ppl that use them.
I personally do not use them for two reasons:
1. Sanitary Reasons. It is almost impossible to get all bacertia out of them.
2. This time of year is probably the worst time to try since the jugs you plug them into if they are not in a heated enviroment they will freeze.
We my many years of raising chickens I find the best solution to watering in the winter is Rubber livestock feed tubs. And in the winter, I use the hanging waterers up off the ground. It's worked for me for years and I like changing water often all the time so that my birds always have fresh. I also like to weekly clean and scrub them well with Oxine then I drip dry them in the sun.
The folks I know that use them swear by them but, I did try them out and between the leaking, freezing, and inability to properly clean them, I ditched them
Our winter doors have been installed, and we like to play with plexiglass so now I'm trying to think of a cool design to cut into the doors
I thought they would cut out alot of light when closed, but it's good when standing inside the porch ~the other windows/vents/light sources are fine. So we don't have to cut a design in, would be an extracurricular project.
For Spring I also want to paint inside the Hen House
something light & bright, maybe a rainbow, possibly a silhouette of a tree.
In the back wall space, shown in this very "old" photo: