@electrycmonk - Hello! ^^ I've got a few DIY waterers who look like what you mentionned, bookmarked for reference. These are the ones I found most interesting:
Stock Tank Heated Horizontal Nipple Waterer by blackdog043
DIY Heated Waterer by Reedo5
In both cases, the rubber grommets, horizontal nipples and water heaters are missing from my amassed list of items needed to build my waterer. The covid-19 did not do me any favors money-wise this year, so until the prices decrease online and in stores, I won't be able to buy anything to try out a DIY heated waterer of my own making.
On that note, aquarium heaters are much more affordable than the stock tank de-icer on amazon. My only hesitation in fetching one from the local pet store is how well they perform outside the tropical setting they were built for.
@Reedo5 , what says you with your 50W Tetra aquarium heater's performance? Can it withstand subzero temperatures without breaking, and even thaw itself out without problems if the water freezes during a power outage? (Do I need higher wattage against against colder temps, is there a certain level of wattage I must avoid to keep the bucket's plastic from melting and mixing with the water?)
@aart - I got my flock on vertical nipples when they were chicks last year, still in the brooder. I had removed any other water source. It took me an hour of teasing the dripping nipple with my finger for them to catch on, and after that they were fine. They even enjoyed the challenge.
This year when I tried the same thing with cups, they were adults and it was late spring. I took out all water sources and put the cups at easy reach. Then I sat down, teased the nipple cup every time a hen came near (spent an hour at this), and even put a few black sunflower seeds in them to peak their curiosity.
They drank the water in the cups without problems. But when there was no more water, I did my best to show them they could have more coming if they fiddled with the yellow nipple. Except the flow of water was so
slow to come out that the hens preferred to go look elsewhere than spend literal minutes waiting to gulp down a mere tablespoon of water. When they did not find the water bowl in the run or enclosure, they went back to foraging the run and never gave the nipple cups another glance again. I left them two hours like this before giving them water, afraid they'd dehydrate.
I tested the cups myself afterward, checking to see how fast the water flowed, and if the first time was a fluke. The flow was... distressingly slow. I'm not sure how fast water must refill a nipple cup, but mine looked like it was below average speed. I deemed those items unsafe to use in hot weather and never tried them again. Another point I discovered in this thread's comments is that they also freeze in wintertime, and that's a big no-no for me.
So, I've only got horizontal nipples to try out now, hopefully these ones perform better than the other poultry nipples xD