Not sure I've seen this before, though I'm sure it's been done before.
Standard five gallon
bucket with poultry nipples screwed into the bottom, I've been using the setup for years and it's worked flawlessly. A manual check of the
water every day or so, and a manual fill up from the hose every week or so, and the birds are good to go.
A few months ago the bucket's handle failed, and the whole setup tipped over and water was unavailable to the
chickens for ? hours, but the hens got vocal and let me know they were out of water before any harm was done. That was when it was cool out.
Now it's getting into the hundreds (F) temperature wise, and I thought it would be a good idea to have a redundant bucket in case of a failure again.
This time, though, I hooked up a 1/4" drip line (coming off of my vegetable garden's drip 1/2" supply line) and then installed a simple float valve (an old swamp cooler float valve to be exact) inside the bucket. My garden gets watered for several minutes twice a day so the bucket is pretty much filled 100% with fresh water twice a day. Theoretically I'd never have to water the hens during the summer. (I still manually fill the original bucket, and keep an eye on both buckets to make sure everything is working properly). When I come across another swamp cooler float, I'll probably automate the original bucket as well.
A bunch of float valves on Amazon.
https://www.amazon.com/s?k=float+valve+swamp+cooler&i=prime-instant-video&ref=nb_sb_noss_2
Poultry nipples I'm using.
https://www.amazon.com/s?k=poultry+nipples&i=prime-instant-video&ref=nb_sb_noss
Cheap insurance, and not too difficult especially if there's already a drip line available.