We have a friend that has what I would describe as toy plastic horses.  About 6 to 7 inches tall.  

She goes to shows with them and enters them into some kind of judging.  

These horses as far as we can tell are ones you buy and don't do anything to them.  There are no modifications of any kind.

She's never been able to explain how the judging works or what makes one bought horse different from another.  We gather that they're all the same breed and maybe the same markings and color. 

Just can't figure out the way you'd judge two plastic horses that are purchased and nothing done to them to improve or differentiate one from the other. 

I'm not criticizing the person's choice of enjoyment, just trying to understand how it works. 

Anybody have any experience with this and want to explain it?