Poop everywhere, How can I control this
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Photos of your coop interior will help as there are many possible "fixes" to this, but not all may be suitable for your setup. The easiest fix is to make the top of the boxes inaccessible or not suitable for sitting on -- this can be accomplished in a number of ways - in our case I had the nest boxes constructed so that there is a "roof" over them that is at a 45 degree angle and smooth, this surface makes it impossible for anyone to land on/stay on that surface.
Is the roost higher or lower than the top of the nest boxes?