I have found a few of these in my coop, and am not sure what they are. They appear to be soft shells. I have five leghorn hens but I can't be sure which ones are laying because they never lay in the nesting box. They usually lay in some small spot on my porch or around the yard so I can't tell who is laying these shells. I did notice one hen had pasty butt, but again I can't be sure if it is the hen laying these shells. They are fairly young, a few weeks short of 5 months. I didn't know if anyone has had this happen and what to do about it? Please let me know, thanks!