Sheep Feed Storage and Preservation: Minimizing Waste and Mold

By Dr. Zubair Khalid, DVM, MS, PhD · 2026-08-14

Key Takeaways

• Moisture is the primary driver of mold growth in sheep feed; hay baled above 18-20% moisture and grain stored above 13-14% moisture are at high risk. Controlling moisture through proper drying, storage elevation (pallets, gravel), and airflow is critical to prevent spoilage and mycotoxin development.
• Nutrient degradation occurs even without visible mold due to respiration, leading to significant dry matter, protein, and vitamin losses, especially in uncovered hay. Outdoor hay storage can result in 25-40% dry matter loss per season, necessitating strategies like gravel bases and bale orientation to mitigate exposure.
• Mycotoxins produced by molds can cause severe health issues in sheep, including reproductive failure, immune suppression, and liver damage, with young lambs and pregnant ewes being most susceptible. Visible mold, musty odors, or heating are indicators of compromised feed, and suspect feed should be tested for mycotoxins before consumption by vulnerable animals.
• Effective pest control, particularly rodent exclusion and trapping, is vital as rodents contaminate feed with droppings and urine, and their damage facilitates mold entry. Sealing building gaps (mice through dime-sized holes, rats through quarter-sized) and maintaining clean storage areas are foundational to preventing infestations.
• First-in, first-out (FIFO) rotation is essential for feed preservation, ensuring older feed is used before it degrades significantly. Storing new feed behind or on top of older stock and organizing storage to facilitate easy access to older inventory minimizes spoilage and maximizes feed value.
• Regular monitoring of feed temperature and moisture, especially during seasonal changes and the critical first weeks post-harvest, allows for early detection of spoilage. Utilizing moisture meters and thermometers in grain bins can provide objective data to prevent heating events and moisture migration that lead to mold.

Feed is the largest variable cost in most sheep operations, and the way you store it determines how much of it actually reaches the rumen. Poor storage practices quietly steal from your bottom line through mold contamination, nutrient breakdown, rodent damage, and spoilage that sheep refuse to eat. This guide covers practical systems for storing hay, grain, and other feedstuffs, with step-by-step methods to prevent mold, control pests, and preserve feed quality from harvest through feeding. It is written for sheep farmers managing small flocks to large commercial operations, and it focuses on actionable strategies you can implement with the facilities and equipment you already have or can reasonably build.

At a Glance

• Store hay under cover with airflow, never directly on the ground, and keep bales off the soil with pallets or gravel.
• Keep grain at or below 13 percent moisture for long term storage and check it weekly during humid weather.
• Use first in, first out rotation so older feed moves to the front of the pile or bin.
• Inspect all feed before feeding and discard any bales or grain that show visible mold, musty odor, or heating.
• Control rodents and birds with exclusion, traps, and good housekeeping around feed storage areas.
• Monitor feed temperature and moisture regularly, especially during seasonal changes.
• Test suspect feed for mold toxins before feeding to pregnant ewes or lambs.
• Call your veterinarian or extension agent if you see signs of mold toxicity, feed refusal, or unexplained illness in the flock.

Understanding Feed Spoilage and Loss

Feed losses happen in two ways. First, there is physical loss, where feed disappears through spoilage, pests, wind, or weather. Second, there is nutritional loss, where the feed remains but its value drops because proteins degrade, vitamins oxidize, or energy content falls. Both types of loss are preventable with the right storage approach.

How Mold Develops in Sheep Feed

Mold requires three conditions to grow: moisture, oxygen, and a food source. Sheep feed provides the food source, so your job is to control moisture and oxygen. Mold spores are present everywhere in the environment, on plants in the field, in the air, and on storage surfaces. When conditions are right, those spores germinate and spread rapidly.

The moisture threshold matters more than any other factor. Hay baled above 18 to 20 percent moisture will heat and mold, sometimes within days. Grain stored above 13 to 14 percent moisture is at high risk for mold growth. The exact threshold depends on the feed type, the storage container, and the ambient humidity, but these general numbers give you a working baseline.

Oxygen is the second factor. Most feed molds are aerobic, meaning they need oxygen to grow. This is why sealed silage bags and oxygen limiting storage work so well. When you exclude oxygen, you stop the mold. But most sheep farms store dry hay and grain, which are exposed to air, so you must rely on moisture control and rapid turnover instead.

Temperature also plays a role. Mold grows fastest between 77 and 95 degrees Fahrenheit, but it can grow at much lower temperatures, just more slowly. In cold climates, mold growth slows during winter but does not stop entirely. In warm humid climates, mold pressure is constant and requires aggressive management.

Nutrient Losses From Poor Storage

Even without visible mold, feed loses nutritional value during storage. The most significant losses come from respiration, where plant enzymes continue to break down carbohydrates and proteins. This process generates heat, which accelerates further nutrient destruction.

Hay stored outdoors uncovered can lose 25 to 40 percent of its dry matter over a single season. That is not just wasted material, it is wasted protein and energy that you paid to produce or purchase. The outer few inches of exposed bales suffer the worst damage, but the entire bale can be affected if rain penetrates deep into the package.

Grain losses are less dramatic but still meaningful. Stored grain loses vitamin content over time, particularly the B vitamins and vitamin E. Protein quality declines as heat damages amino acids. Fats become rancid, which reduces palatability and can cause digestive upset. Under good storage conditions, grain retains most of its feeding value for six to twelve months, but beyond that, losses accelerate.

The Hidden Costs of Feeding Spoiled Feed

Feeding spoiled feed costs more than the value of the discarded material. Sheep that consume moldy feed may suffer from reduced intake, digestive upset, and in severe cases, toxicity. Mold toxins, called mycotoxins, can cause reproductive problems, immune suppression, liver damage, and even death.

The most common mycotoxins in sheep feed include aflatoxin, produced by Aspergillus species, and the Fusarium toxins like deoxynivalenol (DON) and zearalenone. Ruminants are somewhat more tolerant of certain mycotoxins than monogastric animals because rumen microbes can degrade some toxins. However, high levels or prolonged exposure still cause problems, especially in young lambs and breeding stock.

Feed refusal is often the first sign of a problem. Sheep have a keen sense of smell and will reject feed that smells musty, fermented, or off. A ewe that refuses feed loses condition, produces less milk, and may fail to breed. A lamb that refuses feed fails to gain weight and becomes more susceptible to disease. The economic impact of reduced performance often exceeds the cost of the spoiled feed itself.

Hay Storage for Sheep

Hay is the backbone of most sheep rations, and it presents the biggest storage challenge because of its bulk. You cannot put a ton of hay in a sealed bin, so you must work with the space you have and the climate you live in.

Choosing a Hay Storage Site

The ideal hay storage site is well drained, exposed to sun and wind, and protected from prevailing weather. Avoid low spots where water collects and areas shaded by trees or buildings, because shade slows drying and keeps humidity high. The site should be close enough to your feeding area to minimize hauling distance but far enough from the barn to reduce fire risk.

Gravel or crushed stone makes the best base for hay storage. It provides drainage, keeps bales off the soil, and prevents capillary moisture from wicking up into the bales. If you cannot use gravel, a thick layer of pallets works well. Never place bales directly on bare soil, because soil moisture will penetrate the bale and create a perfect environment for mold.

Covered Hay Storage Options

A pole barn with a roof but open sides is the gold standard for hay storage. The roof keeps rain and snow off, while the open sides allow air circulation that keeps bales dry. Orient the barn so the prevailing wind blows through the open sides. This design works well in most climates and is relatively inexpensive to construct.

A fully enclosed barn provides the best protection but requires more attention to ventilation. Hay stored in a tight barn can trap moisture and heat, especially if the hay was baled on the wet side. If you use an enclosed barn, provide ridge vents, eave vents, or fans to keep air moving through the hay.

For smaller operations, a simple tarp system can work if you manage it carefully. The key is to keep the tarp off the hay surface so condensation does not form on the underside and drip back into the bales. Use a frame or place spacers between the tarp and the hay. Weigh down the tarp edges with tires or sandbags to keep wind from lifting it. Inspect tarps regularly and replace them when they develop holes.

Outdoor Hay Storage

Sometimes covered storage is not available, and you must store hay outside. This is common for large round bales that will be fed within a few months. Outdoor storage is workable, but you must accept higher losses and plan your feeding order accordingly.

For outdoor round bales, the most important rule is to keep the bottom of the bale off the ground. Place bales on a gravel pad, old pallets, or even a layer of crushed rock. The ground contact area is where the worst spoilage occurs, and that spoiled layer is exactly what sheep will be forced to eat last.

Bale orientation matters. Some research suggests that storing round bales with the flat ends facing north and south reduces sun exposure on the curved surface and improves drying after rain. The practical takeaway is to orient bales so they get maximum sun and wind exposure on the curved surfaces.

Plastic wrap or bale sleeves can protect outdoor bales from rain, but they create a different problem. Wrapped bales can heat and ferment if the hay was baled too wet, and the plastic creates a greenhouse effect that can cause condensation. If you wrap bales, monitor them closely for the first few weeks after wrapping.

Hay Storage by Bale Type

Small square bales are the most vulnerable to moisture damage because of their high surface area to volume ratio. They must be stored under cover, stacked on pallets, with air space between rows. Stack them in a crisscross pattern to allow air movement through the stack. Do not pack them so tightly that air cannot circulate.

Large square bales can be stored outdoors if they have a dense, well formed package that sheds water. The key is the bale density and the quality of the bale surface. A dense, smooth bale will shed water like a roof, while a loose, rough bale will absorb moisture like a sponge. If you store large squares outdoors, place them on a well drained base and leave space between bales for airflow.

Round bales are the most forgiving of outdoor storage because the curved top sheds water effectively. The bottom and the outer few inches will spoil, but the core usually remains good. Plan to feed the spoiled outer layer to less sensitive animals or discard it, depending on how bad it is.

Hay Stacking and Airflow

The way you stack hay affects how well it stores. The goal is to maximize airflow while maintaining stability. For small squares, stack them on edge with the strings or twines running vertically. This allows air to move between the bales and reduces the chance of moisture trapping.

Leave a gap between the hay stack and any walls. This gap allows air to circulate behind the stack and lets you inspect the back of the stack for moisture problems. A six inch gap is usually sufficient.

Do not stack hay to the ceiling in a low barn. Leave at least two feet of space between the top of the stack and the roof. This space allows heat to escape and prevents condensation from the roof from dripping onto the bales.

Hay Moisture Management

The moisture content at baling determines how well hay stores. For small square bales, target 15 to 18 percent moisture at baling. For large round bales, 15 to 18 percent is also the target, but these bales can tolerate slightly higher moisture if they are dense and well formed. Large square bales should be at 15 percent or below because they pack so tightly that moisture cannot escape.

If you bale hay that is too wet, you cannot fix the problem with storage. The mold will develop regardless of how well you stack the bales. The only options are to feed the hay quickly before it spoils, or to discard it. Some farmers use preservatives like propionic acid to allow baling at higher moisture, but these products add cost and do not work in all conditions.

Grain Storage for Sheep

Grain is easier to store than hay because it is less bulky and can be placed in sealed containers. But grain has its own set of challenges, including moisture control, insect infestations, and the risk of mycotoxin development.

Grain Moisture Targets

The target moisture for stored grain depends on how long you plan to keep it and your climate. For short term storage of a few months, 14 percent moisture is acceptable. For storage beyond six months, aim for 12 to 13 percent. In humid climates, you may need to dry grain even further to prevent moisture migration.

Moisture migration is a serious problem in stored grain. As the seasons change, temperature differences between the center and the edges of the bin cause moisture to move. The moisture can accumulate at the top of the bin or along the walls, creating pockets of wet grain that mold and spoil. Regular checking and occasional aeration can prevent this problem.

Grain Storage Bins and Containers

Steel bins with aeration floors are the best option for long term grain storage. The aeration system allows you to push air through the grain to equalize temperature and remove moisture. If you are buying a bin, choose one with a perforated floor and a fan sized for your bin diameter.

For smaller operations, plastic trash cans, metal drums, and even heavy duty plastic totes work well. The key is to use containers that seal tightly to exclude moisture and pests. A five gallon bucket with a tight lid holds about 30 pounds of grain, which is a convenient size for weekly feeding.

Never store grain in bags that have been used for chemicals, fertilizers, or other non feed products. The residue can contaminate the feed and harm your sheep. Use new bags or bags that have only contained feed.

Grain Cleaning Before Storage

Clean grain stores better than dirty grain. Fines, chaff, and broken kernels create pockets of poor airflow and trap moisture. They also provide a food source for insects and mold. Run grain through a cleaner before storage, or at minimum, screen it to remove the worst of the fines.

If you cannot clean the grain, at least be aware that the fines will concentrate in certain areas of the bin. The center of the bin, where grain falls from the auger, typically has the highest concentration of fines. This center column is where moisture problems will start.

Grain Bin Management

Fill bins gradually and spread the grain evenly to minimize the concentration of fines in one spot. A grain spreader is ideal, but you can achieve similar results by moving the fill spout around the bin as you fill.

Run the aeration fan after filling to equalize the grain temperature with the outside air. This is especially important if you are storing grain from a warm harvest into cold fall weather. The goal is to cool the grain to below 50 degrees Fahrenheit as quickly as possible. Cool grain resists mold and insects better than warm grain.

Check stored grain at least weekly during the first month after filling, then monthly during stable weather. Look for signs of moisture, heating, or insect activity. Probe the grain with a thermometer if you have one, or simply stick your hand into the grain to feel for hot spots.

Grain Storage in Humid Climates

Farmers in humid regions face special challenges with grain storage. The ambient humidity can raise the moisture content of grain stored in breathable containers, even when the grain was dried properly at harvest. In these conditions, sealed containers are essential.

Consider using food grade plastic barrels with gasketed lids for small scale storage. These barrels exclude humidity and protect the grain from insects. They are available from feed stores, bakeries, and restaurant supply companies. Clean them thoroughly before use and inspect the gaskets regularly.

If you store grain in bags in a humid climate, keep the bags off the floor and away from outside walls. Use pallets and leave space between bags for air movement. Check the bags regularly for condensation, which can form when warm grain meets cool air.

Preventing Mold in Sheep Feed

Prevention is always cheaper than treatment. Once mold takes hold in a bale or bin, you cannot fully reverse the damage. Your focus should be on keeping mold from starting in the first place.

The Critical First Weeks

The first two to four weeks after harvest are the most dangerous for feed. Freshly baled hay and freshly harvested grain are still respiring, which means they are generating heat and moisture. If the feed is even slightly too wet, this respiration can spiral into a heating event that ruins the entire batch.

Monitor new feed closely during this period. Check bales for internal temperature by probing with a thermometer or simply feeling the surface for warmth. A bale that is warm to the touch is heating and needs to be fed quickly or spread out to cool. For grain, check the temperature in the center of the bin where moisture concentrates.

Identifying Problem Feed

Learn to recognize the signs of spoilage before they become severe. The first sign is usually an odor change. Fresh feed has a pleasant, sweet or grassy smell. Spoiling feed smells musty, sour, or like fermented silage. Trust your nose, if it smells wrong, it probably is.

Visible mold appears as white, gray, green, or black growth on the feed surface. Some molds are powdery, while others look like cobwebs or fuzzy growth. Any visible mold means the feed is compromised, and you should not feed it without testing.

Heating is another warning sign. Feed that is hot to the touch or steaming in cool weather is undergoing active spoilage. This feed will continue to degrade and may even catch fire in extreme cases. Move it away from other feed and use it as quickly as possible, or discard it.

The Problem With Feeding Moldy Feed

Feeding moldy feed to sheep is a gamble. Some mold species are relatively harmless, while others produce dangerous toxins. You cannot tell by looking at the mold which type it is, and you cannot tell how much toxin is present without laboratory testing.

The safest approach is to discard visibly moldy feed. This is the recommendation of most extension services, and it is the only way to guarantee you are not exposing your flock to mycotoxins. The cost of replacing the feed is almost always less than the cost of treating sick animals or losing lambs.

If you must feed slightly moldy feed because of economic necessity, feed it only to mature, non pregnant animals. Never feed moldy feed to pregnant ewes, lactating ewes, or lambs. These animals are the most susceptible to toxin effects. Mix the moldy feed with good feed to dilute the toxin concentration, but understand that this does not eliminate the risk.

Using Mold Inhibitors and Preservatives

Several products are available that inhibit mold growth in feed. Propionic acid and its derivatives are the most common. These products work by lowering the pH of the feed, which creates an environment where mold cannot grow. They are most effective when applied at baling or at harvest.

Mold inhibitors add cost to your feed program. Before using them, consider whether your storage system is adequate. If you are storing hay under cover on a dry base, you may not need a preservative. If you are storing outside in a humid climate, a preservative might be a worthwhile investment.

For grain, some farmers use food grade diatomaceous earth as an insect control and mold preventive. Diatomaceous earth is not a mold inhibitor, but by controlling insects it reduces the damage that allows mold to start. Use food grade product only, never pool grade.

Rodent and Pest Control in Feed Storage

Rodents and insects do more than eat feed. They contaminate it with droppings, urine, and hair, and they create damage that allows mold to enter. A comprehensive pest control program is essential for protecting your feed investment.

Rodent Control Strategies

The first step in rodent control is exclusion. Seal all gaps and holes in feed storage buildings. Mice can squeeze through a hole the size of a dime, and rats can get through a hole the size of a quarter. Check doors, vents, and utility penetrations, and seal them with steel wool, caulk, or expanding foam.

Keep the area around feed storage clean. Rodents need shelter and food, and a cluttered storage area provides both. Mow grass and weeds around the storage building, remove piles of junk, and keep spilled feed cleaned up immediately.

Trapping is effective for small infestations. Snap traps are reliable and inexpensive. Place them along walls where rodents travel, with the trigger facing the wall. Check traps daily and reset as needed. Glue boards work for mice but are less effective for rats.

Rodenticides are effective but require careful management. Use bait stations that are tamper resistant and placed where sheep cannot access them. The poison takes several days to work, and rodents may die in the feed storage area, creating a contamination risk. If you use rodenticides, check the stations regularly and remove dead rodents promptly.

Bird Control

Birds can consume significant amounts of feed and contaminate it with droppings. They are especially problematic around outdoor feeding areas and open storage. Netting over open storage areas is the most effective control, but it is expensive and can be difficult to install.

For grain storage, keep bins and containers covered at all times. Do not leave grain exposed even for a few minutes, because birds will find it quickly. For hay storage, birds are less of a problem, but they can roost in open barns and contaminate bales with droppings.

Scare devices like reflective tape, predator decoys, and noise makers can help, but birds adapt to them quickly. The most reliable approach is exclusion and prompt cleanup of spilled feed.

Insect Control in Stored Grain

Several insects attack stored grain, including weevils, moths, and beetles. These insects not only consume grain but also create heat and moisture that promote mold growth. The best control is prevention through proper moisture management and clean storage.

Inspect grain regularly for insect activity. Look for webbing on the grain surface, which indicates moth activity, and for small holes in individual kernels, which indicate weevil damage. If you find insects, you have several options.

Cooling the grain below 50 degrees Fahrenheit stops most insect activity. If you have aeration, run the fan to cool the grain. For small batches, moving the grain to a cold location works. Freezing grain for 48 hours kills most insects and their eggs, which is practical for small quantities.

Food grade diatomaceous earth is an effective insect control for small scale storage. Mix it into the grain at the rate of about one pound per ton. The sharp particles cut the insect exoskeleton, causing dehydration and death. It is safe for sheep to consume and does not affect feed palatability.

Feed Storage for Different Sheep Production Stages

Different groups of sheep have different feed needs, and this affects how you store and rotate feed. Understanding these differences helps you plan your storage system.

Feed Storage for Pregnant Ewes

Pregnant ewes need consistent, high quality feed, especially in the last six weeks before lambing. This is the time when nutritional deficiencies have the greatest impact on lamb survival and birth weight. Feed for pregnant ewes should be stored with extra care to ensure it retains maximum nutritional value.

Keep the best quality hay for the pregnant ewe group. This hay should be free of mold, dust, and weeds. Store it separately from lower quality feed so it does not get accidentally fed to other groups. Mark bales clearly with the intended use.

Pregnant ewes are also more sensitive to mycotoxins, especially during early pregnancy when toxin exposure can cause embryonic loss. Be extra cautious about feeding any suspect feed to this group. When in doubt, discard the feed or test it before feeding.

Feed Storage for Lactating Ewes

Lactating ewes have the highest nutritional requirements of any group in the flock. They need energy dense feed that is highly palatable, because intake directly affects milk production. Feed for lactating ewes should be stored to maximize palatability and nutrient retention.

Avoid feeding lactating ewes hay that has been stored outside for long periods, because the outer layer loses palatability even if it is not visibly moldy. Sheep will eat the leaves of the hay first, and if the leaves have shattered and fallen off, the remaining stem is low in nutrition.

Grain for lactating ewes should be stored in sealed containers to preserve freshness and palatability. Stale grain that has absorbed odors from the storage area will reduce intake, and reduced intake means reduced milk production.

Feed Storage for Lambs

Lambs are the most sensitive group to feed quality issues. Their digestive systems are still developing, and they have limited ability to handle mold toxins or spoiled feed. Feed for lambs should be the freshest and highest quality you have.

Creep feed for lambs should be stored in small quantities that will be used quickly. This prevents the feed from becoming stale or absorbing moisture. Use containers that seal tightly and store them in a cool, dry place.

If you feed milk replacer to orphan lambs, store the powder in its original sealed bag in a cool, dry location. Once opened, use the milk replacer within the time frame specified on the label. Moisture in the powder can cause clumping and bacterial growth.

Monitoring and Recordkeeping for Feed Storage

You cannot manage what you do not measure. A simple monitoring and recordkeeping system helps you track feed quality, identify problems early, and make better purchasing and storage decisions.

What to Monitor

Check feed storage areas at least weekly. Look for signs of moisture, mold, rodent activity, and structural damage to storage facilities. Feel the surface of hay bales for warmth and check the corners of grain bins for condensation.

Use a moisture meter to test grain and hay periodically. Moisture meters are inexpensive and give you objective data to guide your decisions. Test at different depths and locations, because moisture can vary within a single bin or stack.

Keep a thermometer in your grain bin if possible. A simple probe thermometer that you can insert into the grain gives you early warning of heating. Grain that is more than 10 degrees warmer than the outside air is heating and needs attention.

Recordkeeping Systems

A simple notebook or spreadsheet is sufficient for most operations. Record the date, the feed type, the storage location, the moisture content, and any observations. This record helps you track how feed quality changes over time and identify patterns.

Record when each batch of feed was harvested or purchased and when it was first used. This information supports your first in, first out rotation and helps you plan future purchases. You should be able to look at your records and know exactly what is in each storage location and how old it is.

Also record any problems you find, such as mold growth, heating, or pest activity. This information helps you identify which storage methods work in your conditions and which need improvement. Over time, you will build a knowledge base specific to your farm.

Seasonal Monitoring Schedule

Feed storage needs change with the seasons, and your monitoring should adjust accordingly. In spring, watch for condensation as warm days alternate with cold nights. In summer, watch for insect activity and mold growth in warm humid conditions. In fall, prepare for the new harvest and monitor the transition from old to new feed. In winter, watch for freezing and thawing damage and for moisture migration in grain bins.

Create a seasonal checklist for your feed storage areas. This checklist ensures you do not miss critical checks during busy times of year. Post it in the barn or keep it with your other farm records.

Common Feed Storage Mistakes

Every farmer makes storage mistakes at some point. The key is to learn from them and avoid repeating them. Here are the most common mistakes sheep farmers make with feed storage.

Storing Hay on the Ground

This is the most common and most costly mistake. Hay bales placed directly on soil absorb moisture from the ground, and the bottom of the bale rots within weeks. The spoiled layer can be several inches thick, representing a significant loss of feed.

The fix is simple and inexpensive. Place bales on pallets, gravel, or even a layer of old tires. The cost of the base is far less than the value of the hay you save. Even a few inches of elevation makes a difference.

Ignoring the First In, First Out Rule

When you feed from the newest bales first and leave the older bales for later, you guarantee that the oldest feed will be the most spoiled when you finally get to it. This is especially problematic with hay, which loses quality continuously during storage.

The fix is to organize your feed storage so that older feed is always accessible. Put new feed behind or on top of old feed, and pull from the front or bottom first. If you have multiple storage locations, use the oldest location first.

Overfilling Storage Areas

Cramming too much feed into a storage area reduces airflow and makes inspection difficult. Hay stacks that touch the ceiling trap heat and moisture. Grain bins that are overfilled do not allow proper aeration. Overcrowded storage also makes it harder to practice first in, first out rotation.

The fix is to leave space in your storage areas. This may mean building more storage or reducing the amount of feed you store at one time. The cost of additional storage is offset by reduced losses and easier management.

Not Checking Feed Regularly

Many farmers fill their storage areas at harvest and do not look at the feed again until they start feeding. By then, problems have had months to develop. A mold problem that is caught early can often be managed, while the same problem discovered late may destroy the entire batch.

The fix is to build regular checks into your routine. Spend five minutes in the feed storage area each week. Look, smell, and feel the feed. The time investment is small, and the payoff is significant.

Mixing Old and New Feed

When you add new feed to a bin that still contains old feed, you create a situation where the old feed is pushed to the bottom and may never be used. This is especially problematic with grain, where old grain at the bottom of the bin can spoil and contaminate the new grain above it.

The fix is to empty bins completely before adding new feed, or at minimum, use the old feed before adding new. This requires planning and discipline, but it prevents the buildup of stale feed that plagues many operations.

When to Call a Veterinarian or Extension Agent

Most feed storage problems are management issues that you can solve yourself. However, there are times when professional help is needed. Knowing when to call can save you money and protect your flock.

Signs of Mold Toxicity in Sheep

If you suspect your sheep have consumed moldy feed, watch for these signs: reduced feed intake, decreased milk production, weight loss, diarrhea, lethargy, and in severe cases, seizures or death. Pregnant ewes may abort, and rams may show reduced fertility.

If you see these signs and suspect mold toxicity, call your veterinarian immediately. Do not wait to see if the animals improve on their own. Mycotoxin exposure can cause permanent damage, especially to the liver and reproductive system.

Your veterinarian may recommend blood tests to check liver function and may be able to provide supportive care. They can also help you determine whether the feed is the cause and what to do with the remaining feed.

When to Test Feed

Feed testing is worthwhile when you suspect a problem but are not sure. Laboratories can test for moisture content, mold counts, and specific mycotoxins. The cost of testing is usually far less than the cost of feeding contaminated feed to your flock.

Contact your extension agent or veterinarian for recommendations on which laboratory to use and which tests to order. They can help you interpret the results and decide whether the feed is safe to use. The American Consortium for Small Ruminant Parasite Control and the USDA APHIS Sheep Health program can provide additional resources on feed safety and flock health.

When to Consult an Extension Agent

Extension agents are excellent resources for feed storage questions. They can provide information on local conditions, recommend storage systems that work in your area, and connect you with other farmers who have solved similar problems.

If you are planning a new feed storage facility, consult your extension agent before you build. They can help you design a system that meets your needs and avoids common mistakes. They may also know about cost sharing programs or grants that can help fund your project.

Building a Feed Storage Plan for Your Farm

A written feed storage plan helps you stay organized and make better decisions. Your plan should cover the entire cycle from harvest or purchase through feeding.

Assess Your Current Situation

Start by evaluating your current feed storage. Walk through your storage areas and note any problems. Is the hay on the ground? Is the grain bin leaking? Are there signs of rodent activity? Make a list of issues to address.

Calculate your annual feed needs. How much hay do you feed each year? How much grain? This number tells you how much storage capacity you need. Remember to account for losses, which should be no more than 5 percent with good storage but can be 30 percent or more with poor storage.

Set Storage Goals

Based on your assessment, set specific goals for your feed storage system. These goals should be measurable and achievable. For example, reduce hay storage losses to less than 10 percent, or eliminate visible mold in stored grain, or reduce rodent activity to zero.

Write your goals down and review them regularly. Use them to guide your decisions about storage improvements and management practices.

Implement Improvements Gradually

You do not need to fix everything at once. Prioritize the changes that will have the greatest impact on feed quality and losses. Start with the basics, like getting hay off the ground and sealing grain bins, then move to bigger projects like building a hay barn.

Keep records of the changes you make and the results you see. This information helps you justify future investments and refine your approach over time.

Review and Adjust

Your feed storage plan should be a living document. Review it at least annually, preferably before harvest season. What worked well last year? What problems did you encounter? What changes should you make for the coming year?

Talk to other sheep farmers in your area about their storage systems. Learn from their successes and mistakes. Your extension agent can help you connect with other producers and stay current on new storage technologies.

Frequently Asked Questions

How long can I store hay for sheep?

Hay stored under cover on a dry base can maintain acceptable quality for 12 to 24 months, depending on the forage type and storage conditions. Small square bales stored in a dry barn can last up to two years, while large round bales stored outdoors may need to be used within 6 to 12 months. The nutritional value declines steadily during storage, so it is best to feed older hay first and use hay within one year of harvest when possible. Test older hay for protein and energy content before relying on it as the sole feed source, because the actual values may be lower than you expect.

What moisture level is safe for storing sheep feed?

Hay should be baled at 15 to 18 percent moisture for safe storage. Grain should be dried to 13 percent or below for short term storage and 12 percent or below for storage longer than six months. If you are storing feed in a humid climate, aim for the lower end of these ranges. Use a moisture meter to check feed before storage and periodically during storage, because moisture can change as conditions change. Feed stored too wet will heat and mold, while feed stored too dry may become dusty and less palatable.

Can sheep eat moldy hay?

You should not feed visibly moldy hay to sheep. Mold can produce toxins that cause reduced intake, digestive upset, reproductive problems, and even death. The risk is highest for pregnant ewes, lactating ewes, and lambs. If you have slightly moldy hay and must use it due to economic necessity, feed it only to mature non pregnant animals and mix it with good quality feed to dilute the mold. However, the safest approach is to discard moldy hay and replace it with clean feed. The cost of replacing feed is usually less than the cost of treating sick animals.

How do I keep mice and rats out of my sheep feed?

Start with exclusion by sealing all holes and gaps in feed storage buildings. Mice can enter through holes the size of a dime, so inspect carefully and seal with steel wool or caulk. Keep the area around storage clean and free of clutter that provides shelter for rodents. Use snap traps placed along walls where rodents travel. If you use rodenticides, use tamper resistant bait stations that sheep cannot access. Check traps and bait stations regularly and remove dead rodents promptly to prevent contamination of feed.

What is the best way to store small square bales?

Small square bales should be stored under cover on pallets or a gravel base. Stack them in a crisscross pattern that allows air to move between bales. Leave at least six inches of space between the stack and any walls, and at least two feet of space between the top of the stack and the roof. Do not pack bales so tightly that air cannot circulate. This arrangement allows moisture to escape and prevents heat buildup that can damage the hay.

How often should I check my stored feed?

Check stored feed at least weekly during the first month after harvest, when spoilage risk is highest, and then at least monthly during stable weather. Check more frequently during humid weather, seasonal transitions, or when you have had problems in the past. Look for signs of moisture, mold, heating, and pest activity. Smell the feed and feel the surface for warmth. A quick weekly check takes only a few minutes and can prevent costly losses.

Should I test my sheep feed for mycotoxins?

Test feed for mycotoxins when you suspect a problem or when you are considering feeding feed that has visible mold or an off odor. Testing is also wise for feed that will be fed to pregnant ewes or young lambs, because these animals are most susceptible to toxin effects. Your veterinarian or extension agent can recommend a laboratory and help you interpret results. The cost of testing is usually less than the cost of feeding contaminated feed and dealing with sick animals.

What should I do if my sheep refuse to eat feed?

If sheep refuse feed, first check the feed for signs of spoilage. Smell the feed and look for mold, dust, or off colors. If the feed seems fine, consider other factors like sudden changes in the ration, dirty feeders, or water quality issues. Sheep are creatures of habit and may refuse feed that is different from what they are used to. Introduce new feed gradually over 7 to 10 days. If the refusal continues and you see other signs of illness, contact your veterinarian.

Related Farming Guides

• Feed Storage and Preservation: Minimizing Nutrient Loss on Your Farm

This section will be populated with links to other farming guides on this site that cover related topics such as sheep nutrition, flock health management, and forage production. Check back for updates or use the site search to find additional resources.

Related Clinical & Scientific Guides

• Sheep Grazing Lease: Terms, Rates, and Legal Considerations
• Sheep Breed Selection for Meat, Wool, Dairy, and Low-Input Systems
• Sheep Barn Flooring for Hoof Health: Best Materials and Practices

References

• American Consortium for Small Ruminant Parasite Control (ACSRPC): https://www.wormx.info/
• USDA APHIS Sheep Health: https://www.aphis.usda.gov/livestock-poultry-disease/sheep-goats
• FAO Sheep and Goat Production: https://www.fao.org/animal-production/en/
• FAO Animal Production and Health: https://www.fao.org/animal-production/en/
• WOAH (World Organisation for Animal Health): https://www.woah.org/en/home/

This article is educational and is not a substitute for veterinary diagnosis, treatment, public-health guidance, or regulatory reporting.