Walmart, the largest food seller in the U.S. is committing to using only cage-free eggs, which scored a massive win for those supporting animal rights as well as sustainability.

The largest retailer in the world announced that U.S. Walmart as well as Sam’s Clubs stores are going to transition to 100% cage free egg supply on or before 2025, which is a timetable matched in recent commitments by other large grocers that include Kroger, Supervalu and Albertsons.

A spokesperson for Walmart said that the company’s commitment to the transition to an egg supply chain that is cage free recognizes expectations and represents one more step taken by the company to improve the transparency of food that is sold in our stores and clubs in the U.S.

Walmart, which since 2001 has sold some cage free eggs in U.S. company stores, said it would reach its goal of 2025 based upon the available supply, customer demand and affordability.

The huge retailer also went into detail about specific requirement it was intending to adopt, which includes requirements for perches and nests and a 1 square foot minimum space per hen.

Food makers, restaurants as well as egg suppliers have recently announced commitments of multi-years to use eggs from cage-free hens exclusively, a shift in policy that advocates of animal welfare say is vitally important due to pain caused to the chickens kept in cages that are cramped.

Others joining in on the movement include Trader Joe’s, Sprouts Farmers Market and Safeway.

However, Walmart in particular is very important as it represents 25% of all the food sold across the U.S.

Walmart previously had found it was targeted by the Humane Society that in late 2008 submitted with the retailer a shareholder resolution that called for the company to disclose its plan to shift to eggs from cage free birds.

Later Walmart confirmed that all company private labels in the Great Value label were in fact cage free, leading that group to withdraw that resolution.