Up until now we've been using aspen shavings on the floor in the coop. They've worked well. We clean out the shavings 2x/month and put them in our compost pile, which adds nitrogen to the soil. However, the shavings are expensive and we want to find a more economical option. We've considered putting the straw we use in their run on the coop floor. The problem we envision with that is that the girls LOVE to scratch and move the straw around. It seems like the poop could easily slip through and end up on the wood floor, which makes it difficult to clean. Another possibility is making some kind of container/box, filling it with aspen shavings, and putting it right under their perch. Then we could use straw for the rest of the coop. What would you recommend?