Yep, I've always asserted there is nothing dumber in the woods than a young buck deer. In reality they just seem more 'curious' and more adventuresome than others, but either way...it doesn't bode well for them in areas heavily hunted.
Do they jump in that pen or mainly feed from outside it?
It's a pig corral trap. Deer do go in through the open guillotine door, and they can jump out if they trigger it. It only goes off at midnight, but deer are always checking it out.