The laws were not effective in removing pregnant pigs from gestation crates, as most of the country's pork production is located in less than half of the population. However, in 2016, Massachusetts voted to prohibit the use of gestation crates and prohibit the sale of pork from farms that use these practices. Economists from North Dakota State University and the US Department of Agriculture found that this increase in prices was largely due to "retail amplification" rather than actual cost.