It's probably harder for bison to free range like deer these days. Deer are extremely agile and can leap most fences with ease. Deer are also pretty docile when they're not in rut. Outside of nature preserves it doesn't seem realistic.
An additional data point is that Midewin's bison area is surrounded by a double fence - a barbed-wire one to keep the humans out and a stout steel one to keep the bison in.
I don't think bison really care about fences either. While they don't leap over them, they just walk through them
That’s what I was wondering. Makes sense.
Deer have become almost a nuisance species closer in to Chicago. I’ve seen them in Oak Park about 2 miles away from the nearest forest land. In River Forest, which actually contains forest preserve, things got so bad the village wanted to hire a firm to shoot the deer, but the residents were too shocked by that proposal and it never happened.