could be a malformed egg or maybe something weird they ate... I would keep an eye out to see if you find anything else like that... I'm sure someone on here will have a better idea to what it is
I agree. It looks like egg material, maybe some egg membrane, and some of these weird things are called lash eggs, if they are shaped more like a egg. Usually it is the result of salpingitis, but I'm not sure that this isn't just some extra tissue expelled. There does look to be a skinny round worm in the second picture. That would then make it questionable to possibly come from the intestinal tract. Here is a little reading about lash eggs and salpingitis just to help you identify any more insteresting findings: http://www.the-chicken-chick.com/2014/12/salpingitis-lash-eggs-in-backyard.html https://www.backyardchickens.com/t/637090/my-first-lash-egg-experience