Do you have a padlock on the run, and only you have a key (or combination)? This is incredibly creepy; arm-hair raising level.I don't think it was because of a fox. I haven't seen the vixen for months and I haven't seen the dog foxes that come courting for a while either. Possibly a dog loose in the field. I have a feeling that the problem was human. I can't explain in any rational manner why I think this, it's just I've seen them nervous after people problems and this seems much like it.