They are using the right panels. Pay close attention to that. Hogs can get their heads through cow panels and they'll wiggle the welds loose or else die hanging half way through. Sheep panels are what it takes. Some places call them utility panels if they are only 16 foot long. I like the 20 footers.
Full grown hogs will go right over the top of that one. They'll go over 6 foot panels.
Hogs are what do the pasture damage with their cutter teeth. They root up the ground and the little fellows run in behind and get roots and worms too. The little guys will also flip every cow pie in a pasture as they grub for bugs and worms underneath them.
That trap will hold shoats and pigs (like you see in the picture), so long as they don't go "piggy back" on you and jump out. Big ones will etiher rip it apart or go over it. Those T-posts are enough. I have seen wood posts sheared off.