The new corporate ranking from Mercy for Animals (MFA), a U.S.-based animal welfare group, evaluated 34 of the region's largest egg sellers on their commitments to phase out supplies from caged chickens.
Besides Walmart's Mexican unit, which also operates in Central America, others flagged for failing to make or implement cage-free commitments include supermarket chain Soriana and conglomerate Femsa, which operates Oxxo convenience stores.
All three were also criticized for lacking transparency on their egg suppliers.
Walmart de Mexico declined to comment, while Soriana and Femsa did not respond to questions.
Cramming hens into so-called battery cages where they are unable to turn around or flap their wings is standard industry practice, said MFA Executive Director Leah Garces.
She added that hens are unable to exercise their natural instinct to perch or lay eggs in nests, and the tips of their beaks are shaved off to minimize damage from pecking.
"It's total, extreme animal suffering that's wrapped into each egg," she said in an interview.
MFA's Latin America ranking, based partly on company responses to a survey, also credits big-box retailer Costco and fast-food chain McDonalds for making progress on implementing cage-free supplies.
The ranking comes nearly a decade after the European Union banned eggs produced from caged chickens citing animal cruelty, along with several U.S. states.
Mexicans eat more eggs than any other nationality, or about 23 kg (51 lb) a year, according to the International Egg Commission.
Colombia, Argentina and Peru are also among the top 10 egg-consuming countries.
(Reporting by David Alire Garcia; Additional reporting by Daina Beth Solomon; Editing by Stephen Coates)
By David Alire Garcia