Something awful killed my mare today - any ideas or thoughts? (gruesome details, no photos)

[windswoo]

Well, I've walked the field and am none the wiser. I can see where something happened, because there are suddenly deep prints and turf thrown up, as if she was spinning away from whatever it was. Then there are the patches where she was up and down and rolling, but no dead vegetation anywhere. I just don't know.

I'd go and speak to the people on the scrapyard - just ask if they saw the horses behaving differently on the Saturday and see if they mention anything.
Sorry for your loss.