I have had the same thing happen to my buck target. I leave it up year round right on the edge of our woods. I can home one day last year to see it almost knocked into pieces. The head and whole body was leaning backwards...and there were scrapes all over its headand gouge marks, from some other deer's tines.

It's interesting anyways. I bet it happens at night. Anyways...looks like you have at least one buck in the area. That's a good thing.