I live in Wyoming and pronghorn are thicker’n flies here.
The only reason why those pronghorn didn’t go over that fence is because they didn’t want to. I’ve seen them take big, graceful leaps over cattle fences - they’re able to do it just fine.
They go thru or under fences....
Lot's of WT deer do the same....
I worked on the Walt Whitaker Ranch 20 miles southwest of Douglas, WY. I used to chase pronghorn on horseback. There were hundreds of them on the 10,000 acre spread. They can easily jump barbed wire fences. Seen them go over many times. Used to chase mule deer also. They would slip under low trees and I had to slide off the saddle to the side as my quarter horse would not stop once he was on the chase and would literally have scraped me off at high speed in to a branch! Great fun!