Not so much of an issue with me. My feed is pre screened for metal and my hay is also metal free. The co op runs the feed under an electromagnet before it's put in the grain truck and delivered to my bulk bin so no metal in the ration.
Parts fall off harvesting equipment all the time. I fond various parts laying in the road regularly. Bolts, clips, rake teeth and other stuff. I once found a bumper walking my dog, but no vehicle to be seen. Driver must have been so loaded he didn't realize it had fallen off.