The so-called "ag gag" bills introduced last year in Minnesota and elsewhere were designed, in part, to make capturing undercover footage at factory farms illegal.

Those bills met with widespread resistance both from the public and the media. People saw the value of knowing where their food comes from and how farmed animals are treated.

But the bills are reemerging. Last week, Utah's House of Representatives passed legislation that would make filming on a farm without the owner's consent a misdemeanor.

And last week, Iowa's governor signed into law a bill that would make getting a job on a farm by offering falsehoods on an application a "serious" misdemeanor.

These bills could reemerge in Minnesota, too.

We're beginning to see just how determined the industry is to keep things hidden from us. What do they have to hide?

In the time since these bills were first introduced, three undercover investigations have been publicized which help answer that question.

In November of last year, an investigation by Mercy for Animals exposed cruelties inflicted on egg laying hens at Minnesota-based Sparboe Farms.

We were witness in this footage to hens packed together in battery cages so tightly that each hen was afforded less than a standard sheet of paper's worth of space. We also saw chicks having part of their beaks seared off without any pain relief.

In December of last year, Mercy for Animals released footage from another investigation that documents abuses in a Butterball Turkey factory farm. In that footage, we saw workers beating turkeys with metal bars, kicking them, dragging them by their wings and necks, and throwing them into cages on transport trucks.

And in January of this year, the Humane Society of the United States released footage of the cruelties pigs endure on the factory farms of Seaboard and Prestage, two of the nation's largest pork producers and the main suppliers of pork to Wal-Mart.

In this investigation, we were witness to piglets having their tails and their testicles cut off without any sort of pain relief. We were also witness to mother pigs confined in gestation crates, cages so small that pigs confined in them can't even turn around.

Here was what the industry has to hide. The hens who lay eggs and the pigs and turkeys that wind up on our plates are subjected to many kinds of cruelty and abuse, both at the hands of workers but also because of the standard ways they are raised.

For the industry, the stakes are high in keeping this cruelty and abuse hidden from us.

Mercy for Animals' Sparboe Farms footage moved people to think about how their decisions concerning what to eat affect animals. But it also moved McDonald's and Target to drop Sparboe Farms as a supplier of eggs. Lunds and Byerly's soon followed.

Mercy for Animals' Butterball investigation led to a raid of the Butterball farm and to the eventual arrest of six workers, along with the arrest of a state worker who tipped off the farm in advance of the raid.

The Humane Society of the United States' Seaboard and Prestage investigation also moved people to reflect on their food choices. And just days after the release of this footage, Hormel committed to phasing out the use of gestation crates by 2017.

A little over a week later, McDonald's announced that it will begin requiring suppliers to outline plans for phasing out the use of gestation crates.

The impact of these undercover investigations is important. They help position people to better decide for themselves what kinds of food choices they want to make and what kind of food they want to sell. And when people make different choices, that helps make a difference in the lives of chickens, turkeys and pigs.

These investigations help preserve our autonomy -- and they help animals.

In view of these benefits, and in view of the harms of the industry's secrecy, it seems to me that investigators are justified in bending the truth in order to conduct these undercover investigations.

------------

Jeff Johnson, of St. Paul, is a philosophy professor at St. Catherine University.