The trouble with using 5 gallon buckets to supply water to turkeys and chickens is the fact that you can never tell how MUCH water is left without walking right up to the bucket, taking the top off (if you have one) and looking in.
The solution is simple - a flat section of closed cell Styrofoam with a bright orange indicator sticking up from it. The foam disk floats on the water and the indicator lets you see how much water is left in the bucket. We did modify the original design and spray painted the TOP of the indicator black so it’s even simpler - how ever much orange is showing is exactly how much water is left in the bucket.
We did find having a lid helps (with a hole drilled for the indicator to slide up and down in). In the case of the turkeys, it keeps them from messing with the foam in the water.