available again in November 2016, but at a limited number of McDonald's locations; and once more since October 2017, but in most areas. Local McDonalds Twitter accounts announced in Southern California and Hawaii that the McRib would be returning to these locations on November 2 and 9, 2017 respectively. The McRib once again made a limited return in the United States and Australia at participating locations starting in October 2018. The McRibs rolled out once again for a limited time beginning October 7, 2019. For 2020, McDonald's announced that the McRib would be made available nationwide in the United States for the first time since 2012, beginning on December 2. It was dubbed as "the most important sandwich of the year." It also returned for a limited run, along with the "El Maco Burger", in Australia. On September 30, 2021, McDonald's announced on Twitter that the McRib was returning on November 1 for a limited time. The previous day on September 29, the company tweeted that there was important news coming. The McRib was available at some locations before November 1. On October 23, 2022, McDonald's announced that the McRib would return on October 31, 2022, for what is being called "The McRib Farewell Tour", the fourth such after the 2005 and the 2007 ones. The McRib was available until November 20. HSUS lawsuit In November 2011, the Humane Society of the United States filed a complaint with the U.S. Securities and Exchange Commission against the producer of McRib meat, Smithfield Foods, alleging cruel and unusual treatment of the animals used in the McRib patty production. The complaint cites the use of gestation crates and poor and unsanitary living conditions, as well as a lack of proper animal welfare. McDonald's responded by requiring its U.S. pork suppliers to eliminate the use of gestation crates. Limited availability Speculation on the limited availability of the McRib includes theories concerning the fluctuating price and unreliable supply chains of bulk pork, manipulation of availability windows to turn the product into a better loss leader for the company, and the generation of renewed enthusiasm and higher sales as a result of scarcity. An informal study from 2011 entitled "A Conspiracy of Hogs: The McRib as Arbitrage" illustrates a correlation between the price of pork and the timing of McDonald's offering the sandwich; all five of the US McRib offerings between 2005 and 2011 occurred during