Short answer: A small farm should size its milling equipment from the tonnage it mixes each month, not from the catalogue. A hammer mill sets the particle size and a mixer sets the uniformity, so check both against the feed you need, and buy a second scale for the premix before anything else. Ask every seller for the throughput on the material you actually grind, the power supply it needs, and what happens to the screen and the hammers when the maize is damp.
Key takeaways
- Size the line from your monthly tonnage. A machine that is idle most of the month costs more per tonne than one that runs at its rated load.
- Test the hammer mill on your own maize and soya cake. The rated throughput is for dry, easy grain, and damp or oily material slows it and clogs the screen.
- Buy a mixer that you can fill to its rated batch and run for a set time, then check the mix with a simple uniformity test.
- Weigh premix on a scale that reads to one gram. A kitchen scale is not enough, and the premix is the cheapest line to get wrong.
- Keep dust out of the mill room, guard every belt and pulley, and never reach into a running machine.
The most expensive machine on the farm is the one that sits idle
On a small farm, the costliest milling machine is usually the one that sits under a tarpaulin. It works well on the first dry batch, then the next maize delivery arrives damp, nobody wants to run it wet, and the birds end up on bought feed for the rest of the season. The machine was never the problem. The grain store and the buying plan were.
So the first question is not which mill to buy. It is how much feed you will mix each month, when you can get dry grain, and where you will keep it. Those three answers set the size of everything else. We are a hatchery and importer, not a machinery supplier, so treat what follows as a list of questions to ask a seller and check against your own numbers, not a shopping list from us.
Farmers who do this sum usually end up with a smaller, cheaper line that runs every week, in preference to a bigger one that waits for dry grain. A machine that runs is the one that pays for itself.
Size the line from the tonnage you mix each month
Start with a number. Write down how many kilograms of feed you mix in a typical month, and then divide it by the number of working days. That gives you the daily load, and that is the figure a mill has to meet on your busiest days.
Take a farm that mixes one tonne a month. That is about 33 kilograms a day on average, or roughly 250 kilograms a week if you run five days. A mill with a rated output of a few hundred kilograms an hour will finish that work in well under an hour of running time. The bigger question is how often you run it, and how much of your month the machine sits idle.
Now take a farm that mixes four tonnes a month. The daily load is closer to 130 kilograms, and the choice of mill and mixer changes. A machine that is too small will run for hours and overheat. A machine that is too big will sit for most of the month and cost more in power and maintenance than it saves.
Write the figure on the wall of the feed room. When it changes, you will know whether the line still fits.
Hammer mills: the screen decides the particle size
A hammer mill breaks grain into smaller pieces by striking it with hammers, and the screen at the bottom decides how small the pieces leave the chamber. A finer screen gives a finer meal. A coarser screen gives a grittier meal with more texture. Most small farms need two screen sizes, one for the chick feed and one for the layer or grower mash.
Chick feed is the one that needs care. The particles have to be small enough for the chicks to eat without struggling, but not so fine that the meal turns to dust and clumps when it meets moisture. Ask the seller which screens fit the mill, what sizes they give, and whether the screens are easy to change. A mill where the screen takes an hour to remove will get its screen changed less often than it should.
Test the output. Take a handful of meal after each screen change, spread it on a white tray, and look at it in daylight. If you see large unbroken pieces of maize or soya cake, the screen is too coarse or the hammers are worn. If the meal looks like flour and sticks to the hands, the screen is too fine for the feed you are making.
Check whether the mill has a feed hopper that fills evenly. A hopper that bridges, where the grain forms an arch and stops flowing, will leave the chamber half empty and the meal uneven. A simple agitator or a steady hand on the hopper solves it, but the seller should show you how the machine handles that before you buy it.
Throughput on the material you actually grind
Every mill has a rated output, and it is always quoted for dry, easy grain. Small hammer mills are often rated at a few hundred kilograms an hour on dry maize. Soya cake, groundnut cake and damp grain all grind more slowly, and some of them clog the screen. The rated figure is a starting point, not a promise for your material.
Ask the seller for the throughput on maize, and then ask again for the throughput on soya cake and on any other ingredient you plan to grind. If they cannot give you a figure for the second, test the machine yourself before you pay. Bring a bag of your own soya cake, grind a kilogram, and time it. Then check the screen and the meal.
Moisture is the test that catches most people. Grind a sample of the grain you will use in the rains, not the dry grain from the seller's yard. A mill that grinds dry maize at a good rate can slow to a crawl on grain at higher moisture, and the screen can block within an hour. That is why the store and the grain drying come before the mill.
Do not forget the cleaning. A mill that has ground oily cake needs to be cleared out before it grinds maize again, or the residue sticks in the chamber and the next batch goes off.
Mixers: fill to the rated batch and test the mix
Most small farms use a horizontal paddle or ribbon mixer, or a vertical auger mixer, and both can make good feed if they are run to their rating. The first rule is to fill the mixer to its rated batch and no more. A mixer that is overfilled does not turn the ingredients over, and the bottom of the batch stays unmixed. Read the rating plate and write the batch size on the mixer.
The second rule is to run the mixer for a set time after the last ingredient goes in. A few minutes is a common starting point for a small paddle mixer, but the right time depends on the machine. Use a timer, not a feeling, and keep the time on a card beside the mixer.
Test the mix. Take five small samples from different parts of one batch, using a cup or a small container. Put the samples on a tray, mix each one by hand, and look for colour and texture differences. A food-grade colouring makes this test easy, and it does not need a laboratory. If one sample is clearly different from the rest, the mix is not uniform, and you should change the batch size, the mixing time or the order you add the ingredients.
Keep the mixer clean. Residue from one batch can carry into the next, and that matters most when you switch between a chick feed and a layer mash.
The scale that matters more than the mixer
The cheapest line in the premix is the most likely to go wrong. Premix is added in small amounts, often a fraction of one per cent of the batch, and a kitchen scale that reads to five grams is not accurate enough. If your premix is added at a quarter of one per cent, a 100 kilogram batch takes 250 grams. A scale that reads in steps of five grams cannot weigh that dose reliably, and the smaller additives you add in even tinier amounts are weighed even less accurately.
Buy two scales. Use a platform scale for the bulk ingredients, with a capacity you can use for a full bag, and a small scale that reads to one gram for the premix and any other additive. Keep the small scale in a clean, dry place, and check it against a known weight every month.
Use the dose on the premix label, and check it with your supplier if you are unsure. The label is written for a specific batch size, and if you mix a different size, the dose has to be recalculated. Write the calculation on the card beside the scale, so the next person who mixes can see it.
Weigh every bag of bulk ingredient when it arrives, not only when it goes into the mixer. A bag that is short by five kilograms is a cost you can prove, and a supplier who knows you weigh the bags tends to fill them properly.
Power, phases and what the generator costs per tonne
A hammer mill of the size most small farms buy often runs on a single-phase supply, but a larger mill or a continuous line can need three-phase power. Check the motor rating on the mill, the supply your building can take, and whether the wiring is up to the load. A mill that trips the breaker every time it starts is a fire risk as well as a nuisance.
Many farms run the mill on a generator when the grid is unreliable. That changes the arithmetic. A generator burns fuel by the hour, and a mill that runs for two hours to grind a tonne costs the fuel for those two hours plus the generator's maintenance. Work out the fuel per tonne from the generator's rated consumption, and add it to the feed cost before you decide the home mix still pays.
Solar can cover part of the load in the day, but a mill with a large motor needs a battery or an inverter sized for the start-up surge. Our solar power article covers the sizing side for the whole farm, and the mill should be included in that sum from the start.
Keep a log of hours run and fuel used. A mill that uses twice the fuel per tonne in the third month of the year is telling you about a belt, a bearing or a screen that needs attention.
Grain storage, moisture and the mould that ruins a mill run
The mill cannot make good feed from grain that has already gone wrong. Most grain storage advice aims for maize below about 13 per cent moisture before it goes into a store, and the figure matters more in the rains than in the harmattan. A grain moisture meter is a modest cost and a worthwhile one, and if you do not have one, the seller or your miller can check a sample for you.
Dry the grain on a clean surface, not on the bare ground. A tarpaulin raised off the floor, turned daily, works in dry weather. In the rains, dry the grain in a covered area with airflow, and do not store it until it is dry to the touch and to the bite. Mould in the grain before milling passes into the meal, and a mill that grinds mouldy maize spreads it through the whole batch.
Our feed storage article sets out what to look for in a store, and it is worth reading before you buy the mill, because the store decides how often the mill runs.
Keep the grain off the floor and away from the wall. Pallets, raised shelves and a clear gap for air keep moisture from rising through the bags, and they make it easier to see if a bag has started to spoil. Our feed wastage article covers the losses that come from poor storage as well as spilled feed.
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A simple layout for a one-tonne-a-month line
A small milling line does not need a large building. It needs an order of work that stops grain from going backwards. Grain comes in, is weighed and checked, goes to the mill, then to the mixer, then to bags. Put each machine so that the material moves forward. A mixer placed where the mill's output must be carried back and forth will cost time and spill feed.
The table below lists the main pieces of a one-tonne-a-month line, what each one does and what to check before you pay. We have not put prices in it, because prices change with the seller, the power supply and the specification, and a number we wrote here would be out of date before you read it.
| Equipment | What it does | What to check | Question for the seller |
|---|---|---|---|
| Hammer mill | Breaks grain and cake into meal | Screen sizes, motor rating, hopper action | What is the throughput on soya cake and on damp maize? |
| Mixer | Blends ingredients into a uniform batch | Rated batch size, mixing time, ease of cleaning | How do I test uniformity, and what batch size gives a good mix? |
| Platform scale | Weighs bulk ingredients and finished bags | Capacity, resolution, stability on the floor | Can it be checked against a known weight? |
| Fine scale | Weighs premix and small additives | Reads to one gram, stable, protected from dust | What is the readability and the capacity? |
| Sieve and magnet | Removes stones, string and metal | Mesh size, magnet strength, easy to clean | How often does the magnet need clearing? |
| Bagging scale or bag holder | Fills finished feed to a set weight | Repeatable fill, clear weight display | What is the typical error on a 50 kilogram fill? |
Use the table as a question list. A seller who answers every question clearly is a seller you can work with.
Dust, guards and keeping the mill running
Grain dust is a real hazard. Fine dust in a closed room can catch fire from a spark, and it is bad for the lungs of anyone who works in it all day. Place the mill in a space with airflow, sweep the floor after each run, and keep the dust out of the motor. A mask and ear protection are not a luxury for the person who feeds the hopper.
Guard every belt, pulley and coupling. A loose sleeve, a scarf or a sack string can catch on a moving shaft in a second. Never reach into a running hammer mill to clear a blockage. Switch it off, wait for it to stop, and then clear it with a tool. Keep a fire extinguisher suitable for electrical fires within reach of the mill and the mixer.
Check the earthing before you run the mill for the first time. A poorly earthed motor in a damp feed room is a shock risk, and it is cheap to check with a qualified electrician.
Maintenance is a routine, not an event. Check the hammers for wear each month, tighten belts and bolts, grease the bearings as the maker advises, and keep a log. A mill that is serviced on a schedule runs more hours per year than one that waits for a breakdown, and the log tells you when the next repair is due.
Buy the line, hire a miller, or buy ready feed
Owning a line is not the only way to get home-mixed feed. Some farms hire a local miller to grind and mix a batch to their formula, and bring the ingredients themselves. Others buy a ready feed for the starter and grower, and mix only the layer ration at home. The right answer depends on the tonnage, the power supply and how much time you have to run the machines.
Ask the miller the same questions you would ask a seller. What screens do they use, how do they test the mix, and how do they weigh the premix? A miller who can answer those questions clearly is worth using for a season. A miller who cannot is a risk to the flock, however cheap the batch.
Our home mixing article looks at when mixing pays against buying ready feed, and feed formulation basics shows how to check a mix on paper before you mill it. Read them alongside this one before you commit money to a machine.
Writing the mix card before the first run
Every batch should have a card on the wall, and the card should be written before the mill runs for the first time. It lists the formula for each feed, the batch size, the premix dose for that batch size, the mixing time and the date. When a bird goes off its feed, the card is the first thing you check.
Keep the premix in a sealed, labelled container, away from the bulk ingredients, and use a scoop that is only for premix. A scoop that has been in the salt or the lime bin carries those into the premix, and it is one more way for a batch to go uneven. Our premix article covers what a premix does and what to look for on the label, and salt and minerals explains the other additives that go into the mix.
Date every bag you mix. A batch that is dated, recorded and weighed is a batch you can trace, and that matters if a flock does poorly on one feed and you need to find out why.
A checklist before you buy any milling equipment
Work through this list before you sign for a machine. Most of it is answerable in an afternoon, and it saves a season of regret.
- Write down the tonnage you mix each month, and the daily load on your busiest days.
- Test the mill on your own soya cake and your own damp maize, not only on dry grain from the seller.
- Confirm the screen sizes available and how long a screen change takes.
- Check the mixer's rated batch size and agree a simple uniformity test with the seller.
- Buy a scale that reads to one gram for the premix, and a platform scale for bulk weights.
- Check the power supply, the wiring, the earthing and the fuel per tonne if you run a generator.
- Set up a dry, ventilated store with the grain off the floor and a moisture check before milling.
- Agree a maintenance routine and keep a log of hours run, fuel and repairs.
If you are planning feed for a flock and want to talk through the numbers, call us on +233 24 915 1503. Our frequently asked questions answer the general questions about the birds we supply, and our chick prices sit next to the feed sums in your budget.
Questions farmers ask
What size of hammer mill does a small farm need?
The right size follows the tonnage you mix each month and the number of hours you can run the mill. A farm mixing around one tonne a month needs a mill that finishes that load in a few hours of running time. Ask the seller for the throughput on the material you grind, especially soya cake and damp maize, and test a sample before you pay.
How fine should chick feed be?
Chick feed needs to be fine enough that the chicks can eat it without struggling, but not so fine that it turns to dust or clumps when it meets moisture. Test the output on a white tray, and look for large unbroken pieces or flour-like meal. Choose the screen that gives an even, crumbly meal for the chicks, and a coarser screen for the layer mash.
Do I need a second scale for premix?
Yes, in practice. Premix is added in small amounts, and a bulk scale that reads in large steps cannot weigh it accurately. A scale that reads to one gram protects the dose, and a kitchen scale is not reliable enough for a batch of 100 kilograms. Check the fine scale against a known weight each month.
How do I know if my mix is even?
Take five small samples from different parts of one batch, mix each one by hand, and compare them. A food-grade colouring makes the test easy, and it needs no laboratory. If one sample is clearly different, change the batch size, the mixing time or the order you add the ingredients, and test again before you feed the batch to birds.
Can I run a mill on a generator?
Yes, but work out the fuel per tonne before you decide the home mix pays. A generator burns fuel by the hour, and a mill that takes two hours to grind a tonne uses fuel for those two hours on top of the feed cost. Check the motor's start-up demand against the generator's rating too, as a large motor can trip a small set.
How dry should maize be before milling?
Most storage advice aims for maize below about 13 per cent moisture. Dry the grain on a raised, clean surface and turn it regularly. Do not mill or store grain that is damp to the touch, and check any grain that smells musty or shows mould, because mould spreads into the meal when it is ground.
Should a small farm buy a mill or hire a miller?
It depends on the tonnage, the power supply and your time. A farm mixing a tonne or two a month can often get a good result by hiring a trusted miller for a season, while a larger farm with reliable power may gain more from owning a line. Ask any miller the same questions you would ask a seller, and test their batches before you rely on them.
