Why the shortage? Are we using it to create poison tipped bullets?
Drought. Less corn per acre when it's too hot and/or not enough water. Not a lot can be done about that. Even drought resistant corn only improves the yield. Can't grow crops without water, it's just one of those things. And there is only so much water you can suck out of the ground, or transport by pipe. This is really going to bite us in the tail, btw. I know we all scorn at environmentalists, but vast aquifer depletion is not good in the long run.
Vast oversimplification?
There has been a couple droughts, primarily in the US and EU, of staple grains. Basically, that makes everything cost more. Animals and humans eat those grains. Animals eat a lot of grain to make meat. So a mild bump in grain means very big bumps in meat costs.
Cattle can eat different things than pigs. The stuff that pigs eat is very very expensive, and would cost more than what they think they can sell the meat for later. So, kill pigs now and sell them now. Less feed costs. But there will be shortages later.
Also, by law, we turn feed into ethanol that we put in cars. This is partially to reduce our oil imports and partially because American Corn Growers Association can buy a lot of politicians. Enough politicians to not suspend ethanol for next year. This year's ethanol production is already done. Suspend ethanol mandates, and demand for feed drops. That drops feed prices. That drops food prices across the board. But less profits for feed growers.
There's two ways to make money. Make a lot of stuff and make your money on volume, or make not so much stuff and get paid on scarcity. The second one is hard to pull off in a truly free market, unless it's scarce for a very good reason and alternatives are not cost efficient. But when you're buying politicians, it becomes trivial if you have a fairly decent lobbyist group.