Citation
Unknown. 1927. “A lot of sanitation pigs ranging in age from 10 weeks to 4 months. Photograph used as Figure 6 in U.S. Department of Agriculture Technical Bulletin 374, 1933..” Special Collections, USDA National Agricultural Library. Accessed April 22, 2025, https://www.nal.usda.gov/exhibits/speccoll/items/show/8069.