You may not go for McDonald's Happy Meals but the world's largest fast-food chain is taking steps to ensure that several breakfast offerings include happy bacon and happy sausage.

That's the apparent aim of the Oak Brook, Ill.-based company requiring its pork suppliers to end the use of gestation pens, a nod to complaints by animal rights activists.

McDonald's believes gestation stalls are not a sustainable production system for the future. There are alternatives that we think are better for the welfare of sows, said Dan Gorsky, senior vice president of McDonald's North America Supply Chain Management, in a joint statement with the Humane Society. McDonald's wants to see the end of sow confinement in gestation stalls in our supply chain. We are beginning an assessment with our U.S. suppliers to determine how to build on the work already underway to reach that goal.

The food giant will require suppliers to present plans by May for removing the metal cages.

The two-foot-wide stalls are used to confine sows, which then essentially pump out offspring that become sausage patties and other pork products. The cages are only large enough to allow the sows room to stand. About 5.8 million sows endure the same or similar conditions nationally, according to MarketWatch.

The pro-pig initiative is not the chain's first venture into more humane treatment of animals. McDonald's has required egg suppliers to increase the size of their cages for hens.

The National Pork Producers Council, which represents hog farmers, said it still supports the use of gestation stalls, according to MarketWatch.