He warned on Wednesday that he would launch a proxy fight against the fast-food giant unless it stops doing business with suppliers that keep pregnant pigs in tiny crates for weeks, according to Bloomberg.

In 2012, McDonald’s announced it would stop doing business with pork suppliers that use so-called gestation stalls within 10 years, according to Reuters. The pledge was influenced at least in part by Ichan, who had advocated for swine rights behind the scenes. 

It was Ichan’s expectation that McDonald’s would ban the use of gestation crates altogether, as reported by The Wall Street Journal. Instead, McDonald’s is allowing pork suppliers to use crates until pregnancy is confirmed in female pigs. 

A pig is likely pregnant if it has not menstruated for 17 to 21 days after being bred, but determining pregnancy can take up to 24 days, according to PorkGateway.org. As a result, McDonald’s lets pork producers keep female pigs in crates for up to six weeks into their 16-week pregnancies, according to The Wall Street Journal, or nearly double the amount of time it usually takes to confirm swine pregnancy. 

Gestation stalls—usually two feet in width—are used by pork suppliers to house pregnant swine. The stalls are too small for pregnant pigs to turn around in and have been connected with a number of health issues in pigs. “Foot and leg disorders, urinary tract infections, and cardiovascular problems are also of concern for crated sows, who additionally suffer traumatic injuries and body sores often caused by being forced to stand and lie on unnatural flooring or in residual feces and urine,” according to The Humane Society of the United States. 

Now, after reaching its decade deadline, the burger chain said it needs a two-year extension, citing COVID-related delays and multiple outbreaks of swine disease. McDonald’s confirmed to The Wall Street Journal that it would not meet its 2022 deadline, and is now aiming for a complete phaseout of gestation stalls by 2024. 

Because McDonald’s has backed out of its original commitment, Icahn is threatening to a proxy fight to win board representation at McDonald’s—and to pursue the eradication of gestation stalls from within the company.

“We’re going to fight it as much as we can,” Icahn told Bloomberg TV. “We are probably 90% there from putting up a slate. You know, we’re not going to fool around with them anymore.” 

Icahn is known for buying stakes in public companies that he believes are mismanaged and then pressuring their boards to make changes or sell the business. Early in his career, he gained the reputation as a corporate raider who engaged in hostile corporate takeovers and then stripped companies of their valuable assets.