Yeah, I've known horses that would hook their chin over a fence or bucket and crib.

Cribbing is often genetic. My neighbor breeds TBs and has cribbing in one line, but it always skips a generation. Her horses are all turned out most of the time in big fields with lots of grass and get ridden almost every day. Some crib and some don't. None of them learn it from each other and all the ones that crib started as foals, and are from the same line.