They had eaten a lot of food, ...so I just cleaned the poop out of it (there was a lot) and filled it back up.
This is a big challenge in chicken keeping
. We suspend the feeder and the water from the ceiling of the coop, getting them 4 - 6" of the ground really helps keep things cleaner.
We're experimenting with a watering system that uses nipples - yes, chicken nipples, that's really a thing. You hang a 5 gallon bucket, heated if need be, and there are nipples drilled in to the bottom of the bucket, and the girls learn to drink from them, sort of like a rabbit or hamster's water bottle. That keeps the water much cleaner.