I have recently completed turning two stalls into a coop with an attached yard. I have put a large poop tray under a 12 foot long roost and it is filled with Sweet PDZ (granular, like dry sand). I smoothed out the PDZ with a ruler and locked the coop. I will be getting pullets in 5 days. When I went out today, I found these strange tracks in the PDZ. I can't figure out what could have gotten in, and what would have left these tracks. Please take a look and give me the benefit of your experience. The last thing I want to do is lock my newcommers into the coop only to find them ...well, you know.