Do you have a photo of the property? Are the horses on the same property?
Seems to me that if the pond is not an asset to the property, then it should be filled in so that the water runs as it should.
I hope to God that your friend does know how to check code if he is flipping properties!

I would think people in the town or city hall would know at the building commission or wetlands. Around here, you can't even sneeze near a wetland without risking a violation.

If a child drowning seems like a real possibility, I think you'd want a fence regardless of what code requires.

How have we all survived with all the unfenced streams, rivers, ponds, lakes, drainage areas, etc. all around us. Our old house bordered a 30 acre beaver pond. No fencing on the private or town land (walking trails) surrounding the pond.

Check with your local building department.

Thanks.
They have gotten different answers by same office! Seems you can interpret the book differently! I do not have a pic now, but can do one next time I go up although that will not be untill later.. No, the pond cannot be filled in- it's purpose is to collect run-off water in the warmer months when their horses are hosed off daily after training. It is not a big pond, about 30' round I would guess. Shallow.
I am with chispa-how will this world look/function with everything a 'potential' danger. Geez. I still live with a large irrigation ditch running full tilt through my property in Mt., nobody fences off something like that! Nothing was fenced off, no notices, the woods were there for exploring, the Great Lake Michigan for swimming, etc, etc. gee how did we kids ever survive past childhood?!