I expect the Iowa of my youth had about as much barbed wire per square mile as any state. Intensively farmed, but fields were a lot smaller back then, and all separated by wire fences. Pheasants were the main game, so we were basically hunting ag ground.
My dad's shotgun, which I still have, is an old, beat-up Eastern Arms .410 single shot. Wouldn't have hurt that gun to use it to hold down wire, but I never saw him do that. He used his hand, which I still do. But I'm short enough that holding down the top wire doesn't work in a lot of cases. If I'm with someone else, we take turns stepping on the 2nd strand and pulling up on the 3rd strand while the other guy slides through.
I misjudged the height of one fence this year. Looked like a push down, step over from the road side, but after I'd swung my left leg over and reached for the ground with my foot, I realized there was a depression on the other side, hidden in the grass. So I'm "crotched" on the top strand, and not having slid my gun under the fence, I still have it in my hand. I unload, look for a safe place to drop it so I can use both hands to disentangle myself. I see a big rock partly covered by grass, avoid that. Another nice looking clump of grass, gentle landing for the gun I think. Put the butt down, let it fall . . . clunk. Another big rock hiding in the grass. Untangled, I look for stock damage. Looks like I'm in luck. Reload, continue hunting. About 15 minutes later, I happen to glance at the barrels. Yeah . . . that rock missed the stock, but it caught the barrels a pretty good lick. Nasty dent in the L tube. Didn't have a spare gun with me. Unloaded the L tube, hunted with it as a single shot the rest of the morning. Turned out I only had one chance at a rooster, and I didn't need the L barrel.
