Ag in Action: Learning with Pigs – Supply Chains and Transportation

Target Grade Level / Age Range:


Estimated Time:

30-50 minutes depending on depth


In this lesson students investigate how and why livestock transportation has changed overtime with a focus on pigs. 



Essential Files (maps, charts, pictures, or documents)


  • Supply chain: network between a company and its suppliers to produce and distribute a specific product or service
  • Transportation: movement of food, fuel, and fiber from one place to another

Background – Agricultural Connections   

What is a Supply Chain? 

How does food get to the grocery store? The term supply chain is used to describe the steps involved in the production, processing, and distribution of a commodity. Commodities are things like food, fuel, and fiber. The chain begins with the equipment farmers need to produce food, such as seeds, fertilizer, and machines. Farmers then plant, maintain, and harvest crops or raise animals. The food is cleaned, processed, and packaged before being shipped to grocery stores and into the hands of consumers.  

Transportation in the Supply Chain 

Transportation is a critical part of the supply chain. Transportation, or the movement of goods, is needed in each step of the supply chain. Today we live in a global marketplace for food. Some regions cannot produce certain foods due to population density (lack of farmland), seasons, and climate and soil conditions. Consumers living in these regions rely on farms in other areas to produce their food supply.  

Transportation of Livestock  

Livestock are animals like cattle, sheep, and pigs. Livestock are raised to help feed the world. Farmers work with veterinarians and farm hands to keep their livestock healthy. When livestock are grown farmers sell them. Livestock are sold to be processed. Processing animals turns them into products humans use. Products like bacon, chicken nuggets, and leather. 

To get to the processing plant, livestock have to be transported (moved). Animals used to be transported on foot. Moving livestock on foot was hard. People had to make sure their livestock didn’t run off, get stolen, or killed. Traveling on foot also took time. 

The development of the railroad made transporting animals easier. Livestock could travel further and faster by train than on foot. Transportation can be stressful for animals. Special rail cars were designed to make the journey more comfortable for livestock. A rail car with slats and water misters was invented by Charles J. Karbach. This invention helped to keep animals cool and watered on long journeys. New laws were also created. The Twenty-Eight Hour Law controlled how long animals could be in transport without a break. Despite new inventions and laws, livestock would still die on the rail journey. As time went on, railroads became less popular for transporting livestock.  

Today we use semi-trucks and livestock trailers to move animals. Using a semi-truck allows travel to remote locations. Semi-trucks provide a smoother ride for livestock. Having a smoother ride lowers stress on animals. Less stress lowers the chance of injury and death of livestock. Livestock trailers are specially designed to keep animals safe in transit. The trailers are also designed to make it easy to clean. Keeping a trailer clean lowers the chance of disease spreading from one farm to another. The development of the interstate system has made semi-trucks the preferred way to move animals while following the Twenty-Eight Hour Law.

Learn more about livestock transportation history
Learn more about the Twenty-Eight Hour Law from the USDA and Texas Tech University
Learn more about the transport of pigs from the Animal Welfare Extension, Michigan State University, and the Translational Animal Science Journal

Interest Approach – Engagement (5-10 minutes)

  • Show students the image of a boy moving pigs, train car, and the image of a truck with pigs in the back.
  • Let students know these images show how people used to commonly transport pigs from the farm to market, and eventually processing. 
  • Discuss with students why it’s important for farmers to take their pigs to the market or processing facility. 
    • Potential student answers: people eat pork, money, etc.
  • Set a timer for 1 minute. Have students observe the three pictures and write down what they notice in the pictures. 
    • Penitential student answers: they’re moving pigs, pigs are in a truck, one is a train yard, the yard has places for pigs to stay, there’s a lot of pigs in the truck, etc.
  • Discuss what students noticed and write down these observations under the pictures. 
    • Encourage students to notice what and how the livestock is being moved
  • Let students know that historians often look at the past to determine what life used to be like and to ask questions. 
  • Set a timer for 1 minute. Instruct students to write down as many questions as they can related to the movement of pigs. After the minute is up, have students share their questions with each other and choose 3 to share with the class. 
    • Potential questions: why were pigs moved this way, how are pigs moved today, where were the pigs going, how long did it take to get the pigs to market, why don’t we move pigs this way anymore, etc.
      • For this lesson, students will focus on answering the questions, “how are livestock (pigs) transported today?” and “what caused the change in transportation?”


Explore/Explain (15-20 minutes)

  • Have students read the digital version of the Iowa Ag Today Food & Nutrition. Have them turn to pages 4 and 5. Remind students of the question they are investigating, “How are livestock, like pigs transported today?” Provide students with time to read the centerfold. 
    • Hard copies of the Iowa Ag Today Food & Nutrition are available for request HERE
  • Have students work in small groups or with an elbow partner to share what they discovered from the reading. Have students write down their answer to their question, “how are livestock (pigs) transported today,” using evidence from the text. 
  • Bring the class back as a whole group to share what they learned. Keep track of their findings (answer to the question, “How are livestock, like pigs, transported today?”) on the board.
  • Let students know that they will now investigate another artifact. Instruct students that with this artifact they should put the cards in chronological order and see if it supports their findings in the reading. 
  • Pass out the From Pig to Bacon cards to students and provide them with time to put them in order. 
  • After the cards are in order, discuss with students if the From Pig to Bacon cards support or refutes their findings. 
    • Students will most likely discover that the biggest difference between today’s transport of livestock and the past is the type of vehicle and the number of pigs that can be moved at a time.
  • Remind students that their first question focused on how things are different today compared to the past. Let students know that historians will also work to answer the question of “why” things changed. Remind students know that they will now investigate their second question, “why has transportation of livestock changed?”
  • Pass out the Livestock Transportation Reading sheet. Provide students with time to read the sheet. Then discuss as a whole group what they discovered.
    • This resource has three articles on it. Breaking up the articles may be helpful for students. 

Elaborate (10-20 minutes)

  • Students work with a partner or individually to develop a timeline comic showcasing how transportation of pigs has changed and why. Encourage students to use specific evidence from the readings and activities they engaged in. 



  • Review student's timeline comic for key concepts of going from herding to semi-trucks, causes of transportation change such as animal welfare, mortality, and movement of people. 


Did you know? (Ag facts)

  • Farmers and truck drivers work to maintain animal welfare even in transport. They make sure transport occurs either early in the morning or late in the afternoon, and stocking densities should be reduced by 10% if the temperature is above 77oF.
  • Livestock trailers are designed specifically to increase cleanliness and air flow so animals can maintain as much comfort as possible during transport. 
  • There are laws such as the 28-hour law that protect animals like livestock from being contained for more than 28 hours on a transport vehicle.


Extension Activities 

  • Have students find a route to the processing facility for their own pigs. Using the school as their farm location, students use their knowledge of laws and regulations to create the best route for their livestock.
  • Explore pig structures and functions with the lesson Pigs Structure and Function
  • Investigate how raising pigs has changed over time with the lesson Pig Farming Then and Now


Suggested Companion Resources 





Cathryn Carney 

Organization Affiliation 

Iowa Agriculture Literacy Foundation

Agriculture Literacy Outcomes

  • T2.3-5.d. Provide examples of specific ways farmers/ranchers meet the needs of animals.


Iowa Core Standards

  • Social Studies
    1. SS.4.19. Explain influences on the development and decline of different modes of transportation in U.S. regions.  
    2. SS.4.23. Explain probable causes and effects of events and developments.