My godfather has a bison ranch, one of the larger ones. Regular fences work, as guidance really. If a bison wants to get through, they're weak as water and won

My godfather has a bison ranch, one of the larger ones. Regular fences work, as guidance really. If a bison wants to get through, they're weak as water and won't stop them. You need telephone post thickness fence preferably cemented into the ground if you want to really stop a bison from getting out. If they are in stampede mode, you're screwed, would have to drive I beams into the ground. Bison treat fences as guidelines really, they'll move around it if they're not in the mood to care, but if they are in a "screw this" mood, that fence is going down. Note, when I say regular cattle fence, I mean 8 foot posts driven into the ground, with barb wire every foot to 8 inches apart. Anything less and they tend to work their way through it trying to get at grass on the other side and then no more fence. And that wire has to be taut, like string on a guitar play a note tight. As an anecdote, even with fences like that, he had about 4-5 bison that escaped. Each one got put down to make sure the rest of the herd didn't get escape into their blood.