Once a chicken took a screw that fell out of my hands as I was working on building a coop and ran with it under the grapevines. I sure HOPE she didn't eat it. But there is a possibility.
Also, there was a blue tarp in the run once and a chick ate some of it. And couldn't swallow the whole thing since it was still attached to the rest of the tarp. So we had to cut it off as I couldn't pull it back out of her mouth. I was worried I had hurt her trying to pull it out.
No one seemed to have any future problems from these incidents.
Those were terrifying moments, to say the least.