Already major food providers, including McDonald's, Burger King, Wendy's, Kroger and Safeway have started demanding their suppliers phase out gestation crates.

With a growing number of undercover footage on farm, the Center for Food Integrity (CFI) established an Animal Care Review Panel. This panel analysed the footage earlier this week, commenting: "Overall, these animals were well taken care of. There were no signs of animal cruelty, abuse or neglect. The sows were clean, free of lesions, calm and in good condition."

The panel members note the video inaccurately blames sow gestation stalls for many of the problems animals are experiencing. "The claim that gestation stalls are cruel, inhumane and abusive is not supported by any of the video footage," said one panel member, Janeen Salak-Johnson, University of Illinois.

The panel noted that the size of the stalls appeared to be within guidelines-- that a sow must be able to lay in full-lateral recumbence. A couple of exceptions were noted.

"There is one sow shown with her head laying on a stainless-steel trough," said Salak-Johnson. "But a different angle showed there was adequate room in the stall. Maybe this sow just chose to lay her head on the trough."

It is reported that Costco, buckling under the pressure, has sent a letter to its pork producers to eliminate their confinement of pigs in gestation crates by 2022.

“We want all of the hogs throughout our pork supply chain to be housed in groups…and expect that this transition should be accomplished no later than 2022,“ wrote Doug Schutt, Costco’s executive vice president of merchandising in a letter sent to the company’s pork suppliers this week. “All of us at Costco take animal welfare seriously and consider humane animal handling a business imperative.“

As of yet, Walmart has not responded to the campaign by MFA.

Animal behaviour expert, Temple Grandin has been pushing for an end to gestation crates for a number of years.