a lot.
if you have access to a meadow drag / grater you could also grate the pen to turn over the dirt in the spring. we have also found moving their feed rack to various parts of the pen every couple of months helps distribute their mess evenly!
it's important to keep the pen as clean as you can because of goats' terrible relationship with worms, especially in the spring as things are wet and warm! i hope this post was helpful for anyone interested in raising goats for pets!! please let me know if you have any questions or tips of your own in the comments below! 