I don't know what others do, but here is what I have found:
I tried the whole nine yards- grit, water, and food in each of my coops (and I do have a lot of coops).
The grit bowl overturned.
The water bowl grew mold under it- ewwwww!!! Fuzzy mold.
The food got kicked everywhere. The bigger chickens would go to the smaller chickens' houses and raid the food, terrifying everyone, even though they HAD food in their house.
Now: I have a simple and elegant setup. It mimics the songbird routine for finding food and water.
Food, grit, and water are distributed throughout the run. There are several of each, to reduce competition.
I remove all food when it turns dark and they have gone to the coops. I return when it gets light outside and fill the feeders/waterers.
This works well for me. They don't have to live with mold in their houses. I can easily measure their food intake.