Much of what the activist captured is standard in all large pig farms, but even those people who speak for the industry admit some of the treatment caught on camera amounts to abuse. (CAUTION: Video related to this story is extremely graphic.)
The activist got a job at Iowa Select Farms in Kamrar, Iowa for the past two months.
"I used my real name, my real contact information and I was hired just like any other employee and I did exactly what was asked of me," the activist said.
But, she carried a hidden camera with her and saw what are called "gestation crates." Sows spend most of their lives in seven by two foot cages -- they cannot turn around or easily lie on their side.
"They naturally develop sores on their bodies from the crates and from the flooring, which we know to be extremely painful for them," the activist said.
A ban on gestation crates takes effect in California in four years, but nothing in the law will prevent stores here from buying pork produced this way in other states.
"Unfortunately, there are no federal laws to protect animals during their miserable lives on factory farms, so this type of abuse does run rampant within the pork industry," Mercy for Animals Campaign Coordinator Eddie Garza said.
The activist says she saw other standard industry practices at the farm -- workers clipping piglets' tails and performing castrations with no pain killer. But, the video showed several botched castrations, where the piglets' intestines fall out of their bodies -- some, she says, were left to slowly die.
"Any time an animal is in distress we want to take care of it and make sure it's taken care of medically to cure it or to dispatch it if we have to and that's the last thing we want to do," California pig farmer Steve Weaver said.
Weaver watched the video and questions why workers would handle days-old piglets so roughly.
On the undercover video, an employee explains that it is the farm's practice to send piglets for tail docking or castration by tossing them.
Activist: "We were afraid that if we, like, were throwing them it would, like, mess them up."
Employee: "Oh no, they're fine. Pigs are, piglets are very bouncy I guess you could say."
The employee can also be heard on the video saying, "It's like a roller coaster ride for piglets."
"The things that kind of bothered me was throwing pigs around, it's like throwing anything around that's live, you don't do that," Weaver said.
The employee also instructs workers to kill the sickest piglets by grabbing them by the back legs and smacking them against the concrete floor -- a process called "thumping."
"And you're just going to, the ideal place to hit is right here, to just smash the skull," the employee said.
The activist says she documented piglets slowly dying from injuries and infection and sows who had been bred so many times that their insides are falling out.
The video is quickly making the rounds, including to two companies in the Bay Area who sell pork from Iowa Select Farms -- Safeway and Costco.
"I think the animal handling practices that we saw, they need to be addressed very quickly because they're terrible," Costco Quality Assurance Vice President Craig Wilson said.
Wilson told the I-Team from company headquarters in Seattle Tuesday that Costco auditors will be inspecting Iowa Select Farms' operations in light of the video and will continue pushing for all its suppliers to stop using gestation crates.
"We want great pork, we want safe pork and we want the animals treated well, it's pretty simple in my mind," Wilson said.
Officials at Safeway's Pleasanton headquarters refused to be interviewed on camera, but sent an email saying they have "Halted purchases ... while a thorough investigation is conducted" into Iowa Select Farms and that "Safeway does not tolerate animal abuse" and will continue to increase the amount of pork they buy from suppliers that are phasing out gestation crates.
"Any time that animals are in distress is obviously very concerning for the industry and for fellow producers to see," California Pork Producers Association spokesperson Lesa Carlton said.
The head of the California Pork Producers Association forwarded the I-Team a statement from Iowa Select Farms, that they "take any claims of animal neglect or abuse very seriously" and "Those portions of the video that show violations will be dealt with quickly and appropriately."
"They are going to investigate the situation, they have a zero tolerance policy or any type of mistreatment of animals on their farm," Carlton said.
But, the statement from Iowa Select Farms does not address the issue of gestation crates.