Choosing the right feed mill equipment goes beyond technical considerations. It takes a deep understanding of the entire process—and the science behind it—to pick the best feeders, hammer mills, conveyors, pelleting machines, and other apparatus to process animal feed. Mill equipment must correctly size the grains and other ingredients that go into making animal feed, while the system should be configured to make the process most efficient.

Animal feed manufacturers understand that ingredients must blend uniformly, be as cost-efficient as possible, and suit the digestion system of the animals it’s meant to feed. Mill equipment for making animal feed must thus be customized to fit the exact application, including consideration of the specific type and life stage of the animal. In any feed processing facility, this means having machinery like hammer mills that can properly size and process the raw materials to make a superior end product.

What to Look for in Hammer Mills for Processing Animal Feed

Swinging hammers attached to the rotor spin, making contact with and reducing material, which is usually introduced from the top of the mill. Most hammer mills also feature a screen at the discharge opening to classify products by particle size. Within the hammer mill’s grinding chamber, it’s not just the hammer, but contact between other particles and the sides of the mill that causes particle size reduction. Hammer mills are some of the most versatile types of milling machines, complementing the actions of other feed mill equipment.

Basic Operations of Animal Feed Mill Equipment 

Though significant variations exist in machinery and systems that manufacture animal feed, mill equipment follows a series of general steps to create the final product. Although hammer mills play an integral role in this process, it takes an assortment of other feed mill equipment working together to produce quality feed for animals. The raw material must be received, ground, batched, mixed, pelleted, cooled, sifted, packed, and stored, with each piece of feed mill equipment performing certain tasks.

For an animal feed mill, equipment and basic steps typically follow this sequence: 

  • Receiving: Raw materials that include grain, soy meal, and other ingredients are conveyed by a bucket elevator or other conveying system, cleaned to remove contaminants, and put in storage containers.
  • Grinding: Hammer mills generally grind whole grains and other equipment before mixing them into feed.
  • Batching: Ingredients are weighed by a batch scale before being fed in specific quantities manually or automatically to the next stage.
  • Mixing: The ingredients for each batch are mixed uniformly into a mixing machine; mixing times differ based on formulations, ingredient characteristics, along the type and size of the machine used.
  • Pelleting: Blended ingredients are fed into a feed pellet machine, during which:
    • Feed rate is controlled for mixed ingredients going into the machine.
    • Dry mixed ingredients are steamed and blended in the conditioner, creating a wet mash.
    • Gravity or feeder system causes ingredients to fall into the pelleting chamber.
    • Heated wet mash is pushed through the pellet mill, where pellets are sized and shaped.
  • Cooling: Hot pellets are gravity-fed into a cooling machine.
  • Sifting: Cooled pellets are then sent to the screening machine, where fines and pelleted mash are scalped.
  • Packing: After weighing, a packing machine packages and seals pellets.
  • Storing: Packaged pellets are then transported to a warehouse or other storage area.

In some systems and certain applications, hammer mills may play a dual role, grinding and mixing materials for animal feed. Mill equipment can also differ considerably in size or capacity, depending on the magnitude of the operation.

Choosing the Best Hammer Mills for Feed Production

With so many design variations available for hammer mills, choosing the best one for the application can be challenging. Mill equipment like hammer mills is key to the production process for animal feed makers.

A hammer mill’s operation should effectively: 

  • Size ingredient particles so that they expose more surface area, which allows animals to digest the feed better.
  • Pelletize ingredients to produce quality feed pellets.  
  • Grind raw feed materials to enable easier conveying and delivery.
  • Augment properties of feed ingredients for hammer mills when they are also used for mixing.
  • Allow and adjust for customer preferences.

Additionally, hammer mills incorporated into a feed mill need to have sufficient production capacity, prevent dust and noise, have capabilities to properly grind the materials and discharge to suit the rest of the system, and efficiently utilize power while also being well-supported by the manufacturer.

Production Capacity

Hammer mills must be able to manage the required throughput of a feed mill easily. Equipment should easily handle more than hourly, daily, weekly or monthly requirements. This should include taking into account how wear and tear will affect output over time. Potential growth should also be considered, so it’s often advantageous to purchase a slightly larger machine than needed. Choosing hammermills that just barely handle the expected capacity will likely constrain the production of the entire animal feed mill. Equipment should thus be chosen with careful consideration of future needs. With hammermills, hammer and wear to other components can decrease capacity over time while also affecting the service life of the machine.

Dust & Noise

A downside for hammer mills is the dust and noise they commonly produce. Often, to mitigate the noise and dust that hammer mills produce, operators of such feed mill equipment require PPE (personal protection equipment) and rotary airlocks to prevent dust explosions. The need to finance additional safety equipment to protect from high noise levels and dust-related conflagrations adds to both operational and infrastructure costs.


Factors like the flowability, grain size, moisture content, fat content and temperature sensitivity of the raw ingredients should be considered when shopping for hammer mills. This is especially true when processing these ingredients into powders or small particles, with many of these properties combining to create multiple issues. For example, material with high moisture or fat content tends to be viscous and more challenging to grind. Higher moisture or fat content also reduces the material’s flowability, reducing production efficiency and speed and leading to lower throughputs. For most animal feed mill equipment, the moisture content of the mixed raw material should be at 15 percent or lower. Fat content will vary based on product and fineness but should generally be less than 8%. 

Discharge Methods

Ground product exits hammer mills in one of three ways. Smaller hammer mills generally use a gravity discharge method, which is simplest. For most mid-sized hammer mills, negative pressure is used, which also helps absorb moisture within the raw materials.

Power Requirements

Energy efficiency has become a means to shrink a manufacturer’s carbon footprint and generally run a more environmentally friendly operation. Yet while choosing more efficient hammer mills to use less energy also saves on operational costs, it’s important too that feed mill equipment be sufficiently powerful to do the job. The energy required by feed mill equipment like hammer mills varies greatly depending on the material. For example, the power needed to grind sorghum is half that of corn, whereas the need for power to grind both meals from cotton and soybeans is very similar. Power requirements for hammer mills also depend upon the mesh size of the hammer mill’s sieve.

Other Elements to Consider 

When considering hammer mills, much depends on the type of materials being processed into animal feed. Mill equipment like hammer mills vary widely in configuration, so it’s a good idea to consult with their manufacturers to determine the best type to use for an application.

Other considerations when choosing feed mill equipment like hammer mills include:

  • Grinding chamber diameter: The size of the grinding chamber affects the hammer mill’s efficiency. The diameter should adapt to the screen mesh size and type of raw materials being processed.
  • Maintenance: Keeping any feed mill equipment working effectively requires consistent maintenance;. In contrast, hammer mills are notably robust; the intensity of grinding action will eventually wear out principal components, so regular inspections are necessary to ensure production efficiency and extend a hammer mill’s lifespan.
  • Spindle speed: Higher spindle speeds generally mean more efficient production, but only within a certain range. Lower spindle speeds reduce hammer crushing force, which can result in raw ingredients that are only partly ground; it’s important to find the best speed for a particular material or application.
  • Support: To keep hammer mills running smoothly, a manufacturer that provides service and spare parts for feed mill equipment should be chosen; ideally, a hammer mill’s maker should have an extensive inventory of parts and a strong network of service providers available.  
  • Training: Though hammer mills all work on similar principles, having a more comprehensive understanding of feed mill equipment and how it works within a system will ensure excellent safety for workers and a clearer understanding of what maintenance is required.

Manufacturers of other animal feed mill equipment can often offer good advice on which hammer mills are best for specific applications.

Prater Hammer Mills for Processing Feed

Prater Industries began as a maker of animal feed mill equipment. Prater’s hammer mills have featured in feed milling operations for nearly a century, and our innovative solutions are now used by customers worldwide. Though, as a company, we have evolved and improved our designs, we have never lost touch with the industries that our equipment was built to support.

Prater offers two distinct styles of hammer mills: 

  • G-Series Prater Hammer Mills: As full-screen conventional hammer mills, Prater’s G-series work well for a variety of animal feeds, with several different models to choose from.
  • Prater Mega Hammer Mills: A  cantilevered style hammer mill, Prater’s Mega Mill comes in multiple models and is well-suited for uniformly grinding heat-sensitive ingredients into animal feed in an easy-to-clean design.

Our robust hammer mills continue to be widely used throughout the feed industry, capable of milling uniformly round-the-clock while requiring very little maintenance. With the ability to customize and fabricate prototypes to achieve superior results and improved energy efficiency, Prater continues to provide an exceptional product while also providing excellent support for our customers, including preventive maintenance services. To learn about our hammer mills and other feed mill equipment, contact the material handling experts at Prater today.