Welcome to the forum!
My ducklings (runners, a smallish breed) go through water at varying rates. At first, a quart lasted eight hours or so, that quickly changed, as they grew.
Also, I found that when they do not have opportunity to wash off (at first I used a cake pan and 90 degree F water, then later bathtub up to their bellies again, 90 F), they go through more water trying to clean off.
Keeping clean drinking water before them always is important their first several weeks. I let mine go without food and water overnight ( 6 to 8 hours) once I realized that at night they were mostly just playing and preening.
Food-wise, I have followed the same philosophy of keeping food (sprinkled with a teaspoon of chick sized grit) available to them 24/7. When I removed the water overnight, the food went, too, so they won't choke.
These are some general observations from my experience. I hope they are helpful.
By the way, other than their age, could you tell us what you are feeding them?