You need a composting deep litter system. Has so many benefits, besides keeping the mud down. Here's a thread on it, there's also a much bigger thread on the same topic.
https://www.backyardchickens.com/t/643302/results-from-first-year-with-deep-litter-method
Here's a vid on it...this can be done in a coop and also in the run:
https://www.backyardchickens.com/t/643302/results-from-first-year-with-deep-litter-method
Here's a vid on it...this can be done in a coop and also in the run:
