A recent study was carried out to test whether horses preferred drinking from buckets, a pressure valve bowl (where the horses have to push a plate to get water) or a float valve bowl (where the water automatically refills when it dips below a certain level).
Your Horses’ Drinking WaterKaren Mac (Edinburgh, Scotland)
The study found that horses universally prefer to drink from a bucket.
This is possibly because the bucket, being placed on the floor, more closely resembles your horses natural way of drinking.
And it’s probably easier to get to, if the water bucket has a larger diameter opening.
NOTE: When the test horses were restricted to the two automatic watering systems, it was found the horses spent more time drinking from them, but they took in less water, causing an overall decline in hydration levels.