We use feeding stalls to feed most of our sow herd. Feeding stalls allow us to make sure every sow gets enough food everyday. They also give us the ability to measure out the amount of feed we give our sows, so that they don't get too fat or skinny.
The red droppers above the stalls have a measuring system that we can adjust for change in weather, so the sows get enough food. During the winter the sows get up to 5.5 lbs on the below freezing days and 4 lbs in the summer.
Having each sow get her own stall makes it so the sows don't have to fight for food. This makes their feed consumption more consistent throughout the year.
We are not set up so that every one of our sows eats in a feeding stall all the time. Those sows get fed either by putting feed down at a clean spot in their pen or in a concrete bunk. Their feed is measured out so that every sow in that pen gets enough feed for that day.
If you have any questions feel free to put them in the comments.