The term “barrel of hay” refers to a historical unit of measure no longer used in modern agriculture. Today, hay is primarily sold, transported, and stored in bales, which come in a wide variety of shapes and weights. The actual weight of a hay package is highly variable, depending on the baling method and the condition of the forage. Understanding the factors that affect density and moisture is more useful than seeking a historical weight that is no longer relevant.
Why “Barrel of Hay” is Not a Standard Measure
The term “barrel of hay” likely stems from historical farming practices, where barrels were common containers for measuring or storing commodities. Before modern machinery, farmers used barrels to approximate the volume of loose hay. The modern agricultural industry, however, relies almost exclusively on the bale for standardization. This shift began in the mid-19th century with the mechanization of hay production. Unlike a barrel, which holds loose material, a bale is a tightly compressed and bound package, making it the practical unit for transport and commerce.
Variables That Control Hay Bale Weight
The weight of a hay bale is determined by its moisture content, density, and the species of forage used. Moisture is the largest variable, since freshly baled hay loses significant weight as it cures in storage. Hay baled at the maximum recommended moisture content of 15% to 20% will be heavier than hay that has cured to an equilibrium moisture content. This curing process can result in a weight reduction of 10% or more due to the evaporation of water and the loss of dry matter.
Bale density, or how tightly the hay is compacted, is controlled by the baling equipment and operator settings. For instance, a tightly packed round bale can have a dry matter density of 12 pounds per cubic foot, while a loose bale of the same size might only reach 9 pounds per cubic foot. This difference in compaction can easily lead to variations of several hundred pounds between two outwardly similar bales. The type of forage also contributes to the final weight, as legumes like alfalfa naturally form a denser bale than grass hays such as timothy or bermudagrass.
Typical Weights of Modern Hay Baling Methods
Modern hay is packaged using three distinct methods, each resulting in a drastically different weight range.
Small Square Bales
The small square bale is the traditional package for small-scale farms and horse owners, designed for manual handling. These bales typically measure about 14 inches by 18 inches by 35 inches long. A standard two-string small square bale generally weighs between 40 and 75 pounds. Slightly larger versions, such as three-string bales, are more densely packed and can weigh up to 100 pounds.
Large Round Bales
Large round bales are the standard for bulk feeding in cattle operations and require mechanical equipment for handling. Common dimensions include 4 feet wide by 5 feet in diameter, or 5 feet wide by 6 feet in diameter. Depending on the diameter and the baler’s compaction setting, large round bales can weigh anywhere from 800 pounds to over 1,500 pounds. A dense, 5-foot by 6-foot round bale can contain the equivalent of 20 to 30 small square bales.
Large Square Bales (Industrial)
The largest type of hay package is the industrial large square bale, favored for commercial feedlots and long-distance transport due to its stackable, uniform shape. These bales are compressed to very high densities, with common sizes being 3 feet by 4 feet by 8 feet long. A large square bale of this size generally weighs between 1,000 and 1,500 pounds, though the densest versions can reach up to 2,000 pounds. Their consistent dimensions allow for efficient stacking and maximized payload on semi-trucks, making them the preferred choice for high-volume sales.