Kroger becomes the target of Carl Icahn's animal-welfare campaign, following McDonald's.

• Kroger is becoming the target of Carl Icahn's animal-welfare campaign.
• An activist investor renowned for his advocacy launched a proxy battle against McDonald's, aiming to improve the treatment of pigs.
• Rodney McMullen, Kroger CEO, faced criticism from Icahn regarding compensation disparities between himself and the grocer's median worker.

Carl Icahn is broadening his animal-welfare initiative to the country's largest supermarket corporation, Kroger, following his initial focus on .

Kroger announced on Tuesday that Icahn has proposed nominating two candidates to its board.

Icahn raised concerns about animal welfare and gestation crates in pork production during a discussion with Kroger on Friday.

In his letter to Kroger CEO Rodney McMullen, Icahn criticized the "unacceptable wage disparities" between McMullen and other employees at the company.

Icahn wrote in a letter that the wage gap between Kroger's CEO and median worker is unacceptable. He stated that his candidates will address the issue of deplorable animal suffering and other governance problems at Kroger, including wage gaps, and implement proper oversight.

Icahn's involvement with McDonald's, which he launched a proxy fight over the treatment of pigs, was discussed in an interview he gave last Tuesday. Kroger made an announcement about something on Tuesday, over a month after Icahn's proxy fight with McDonald's.

Icahn stated on "Closing Bell: Overtime" that he was not performing that action for the purpose of earning money.

Icahn's efforts to address animal rights are driven by his emotional response to the cruelty and unnecessary suffering inflicted on animals. He stated, "When I read about the treatment of animals, it bothers me deeply. Whenever I have the opportunity to make a difference, I take action."

Kroger will review Icahn's proposed board nominees, Alexis C. Fox and Margarita Palau-Hernandez, as part of its standard governance procedures. Additionally, the company addressed Icahn's concerns regarding animal treatment.

Kroger is not involved in raising or processing animals, but we are committed to protecting animal welfare in our supply chain. We have a Responsible Sourcing Framework that outlines our policies, requirements, and practices, including our Animal Welfare Policy, which expects suppliers to transition away from gestation crates by 2025.

McDonald's has defended its animal rights policies against Icahn's campaign, stating that by year-end, it expects 85% to 90% of its U.S. pork volumes to come from sows who do not live in gestation crates during pregnancy. The company aims to increase this percentage to 100% by the end of 2024.

Icahn owns a small stake in Kroger and has a similar position in McDonald's. According to a source, Icahn owns 100 shares of Kroger, which is less than 0.13% of the company's fully diluted shares outstanding, as per FactSet.

Kroger's stock closed down 1% on Tuesday at $56.39. Despite this, the stock has gained approximately 25% in value year to date, resulting in a market value of $41.46 billion.

In his letter to McMullen, Icahn stated that his objective for the proxy campaign was not to gain profits, but to address the "glaring injustices" at Kroger. Icahn accused the company's board of inadequate oversight on supply chain policies and compensation. McMullen, who has been both CEO and board chair since 2014, was the target of Icahn's criticism.

Icahn criticized McMullen's compensation increase in 2020, pointing out that the company had previously offered a $2 per-hour raise to store and warehouse workers but later removed it during the early months of the Covid pandemic.

Icahn wrote that the issues of animal welfare and employee wages at Kroger are a violation of basic societal values of decency and dignity. He criticized the company's board of directors for approving unethical policies and breaking promises made to frontline workers during the pandemic.

Kroger has been investing heavily in employee compensation, both before and during the Covid pandemic, according to a spokesperson who defended the grocer's record on this matter.

Over the past four years, Kroger has invested an additional $1.2 billion in associate wages and training, resulting in a national average hourly rate of pay increase from $13.66 to nearly $17, which is a 25% increase. When benefits like health care and pensions are factored in, the average hourly rate is now over $22.

— CNBC’s Scott Wapner contributed to this report.