What to Feed Sheep: Forage, Hay, and the Copper Warning

Author: Elliott Garber, DVM

Feed sheep a diet built on forage: good pasture in the growing season and quality grass or grass-legume hay the rest of the year, with clean water and a loose sheep-specific mineral always available. Grain is a supplement, not the base, and it should be fed sparingly. The single most important rule that sets sheep apart from other livestock: never give them feed or mineral formulated for goats, cattle, or “all-stock” animals, because sheep are highly sensitive to copper and can die of slow, cumulative copper poisoning.

Forage is the foundation

Sheep are ruminants built to turn grass into meat, milk, and wool. A healthy diet starts and ends with forage. On good pasture during the growing season, most mature sheep at maintenance need little or nothing beyond grass, water, and mineral. When pasture runs short or goes dormant, hay takes its place.

For hay, a leafy grass hay or a grass-legume mix (such as a grass-alfalfa blend) suits most sheep. Straight alfalfa is richer in calcium and protein than many sheep need at maintenance, though it is genuinely useful for late-gestation and lactating ewes. Hay should smell sweet and clean, be free of mold and dust, and be stored dry. As a rough starting point, a mature sheep eats roughly 2 to 4 percent of its body weight in dry feed per day, so a 150 pound ewe on hay eats in the neighborhood of 3 to 6 pounds a day, more when pregnant or nursing. Weigh a few bales and do the math for your own flock rather than guessing by the flake.

Because forage quality varies enormously with soil, species, and cutting, a forage test is the only way to really know what you are feeding. Many university extension labs will analyze a hay sample for energy, protein, and minerals for a modest fee, and it takes the guesswork out of whether you need to supplement at all. The Merck Veterinary Manual overview of sheep nutrition is a good reference for the nutrient targets that a forage test lets you check against.

The copper warning: the rule that separates sheep from every other animal

This is the part to read twice. Sheep are the most copper-sensitive of the common livestock species. According to the Merck Veterinary Manual, sheep are the most susceptible species to copper poisoning. The reason is physiological: sheep store copper in the liver efficiently and excrete it very slowly, so copper accumulates quietly over weeks and months with no outward sign of trouble.

Then, often triggered by stress, the stored copper floods out of the liver all at once and destroys red blood cells in a hemolytic crisis. By the time you see the signs, weakness, going off feed, red or brown urine, yellowing around the eyes and gums, the animal is often already dying. There is no reliable home fix once a crisis begins. As Ohio State University’s sheep team and Cornell Cooperative Extension both stress, prevention is the entire game.

What that means in practice:

• Buy feed and mineral labeled specifically for sheep. Products for goats, cattle, horses, or “all-stock” and “all-species” mixes are formulated with copper levels that are healthy for those animals and slowly toxic to sheep. Feeding a cattle or goat mineral is the single most common way sheep are poisoned.
• Read every tag. A mineral or feed can look fine and still list added copper. If in doubt, do not feed it to sheep.
• Do not share feeders across species. If you keep sheep alongside goats or cattle, keep their feed and mineral completely separate. Goats actually need supplemental copper, which is exactly why a shared mineral station is dangerous for the sheep.
• Mind the whole diet, not one ingredient. Copper toxicity is cumulative and driven by dietary balance, not a single toxic dose. Merck notes a dietary copper to molybdenum ratio of 6:1 is ideal and 10:1 is about the tolerable ceiling for sheep. Some breeds, Texel among them, are especially sensitive.

If you suspect any animal has been eating the wrong mineral or feed, stop it immediately and call your veterinarian to discuss the flock, do not wait for symptoms. For a deeper look at getting the mineral side right, see our sheep minerals guide.

Grain: useful, but a supplement with real risks

Grain (corn, barley, oats, or a formulated pelleted concentrate) is energy-dense feed that has its place: pushing ewes through late gestation and lactation, finishing market lambs, and conditioning thin animals. But it is a supplement layered on top of forage, never the base of the diet, and it carries two specific hazards worth understanding.

Acidosis (grain overload). When sheep eat too much grain too fast, or are switched onto grain abruptly, the rumen produces a flood of lactic acid, the pH crashes, and normal digestion breaks down. Ohio State’s small ruminant team describes this as grain overload, and it can range from mild scours and going off feed to a fatal event. The prevention is simple discipline: introduce grain gradually over one to two weeks, keep the amount consistent day to day, and never let sheep break into a grain bin. Store grain where a curious flock cannot reach it.

Urinary calculi (water belly). This one falls hardest on wethers (castrated males) and rams. Grain and grain-based feeds are high in phosphorus, and an inverted calcium to phosphorus ratio drives the formation of mineral stones that can block the urinary tract. South Dakota State University Extension and the University of Maryland Extension both explain that wethers are at highest risk because early castration keeps the urethra narrow. A blocked animal is a genuine emergency: straining, restlessness, kicking at the belly, and no urine passing. Call your veterinarian immediately if you see it.

Prevention for grain-fed males comes down to diet balance and water. Keep the total-diet calcium to phosphorus ratio around 2:1 (extension guidance says never let it fall below 1:1), which usually means not overfeeding grain and making sure calcium is adequate. Many prepared sheep feeds for males include ammonium chloride to acidify the urine, and unlimited clean water is essential. If you are feeding grain to wethers or rams, talk to your veterinarian or an extension nutritionist about getting the ratio right for your specific ration.

Feed to the animal in front of you: body condition through the year

Sheep do not need the same diet all year. Their nutritional demand rises and falls with the production cycle, and the practical tool for matching feed to need is body condition scoring (BCS): feeling along the backbone and short ribs to score each animal from 1 (emaciated) to 5 (obese). Utah State University Extension has a clear guide to the hands-on technique, which matters far more than eyeballing a fleece.

The general targets through the year, drawing on Penn State Extension and sheep.extension.org:

• Maintenance (open, not pregnant). Good forage and mineral are usually enough. Aim to hold ewes around a body condition of 2.5 to 3.5 so they are neither thin nor over-fat going into breeding.
• Flushing (before breeding). Raising the plane of nutrition in the weeks before and during breeding, often with better pasture or a little grain, nudges ewes toward a rising body condition and can improve ovulation and lambs born. The goal is a BCS moving up toward 3 to 3.5, not fattening.
• Early to mid gestation. Demand stays modest; good forage carries most ewes.
• Late gestation (last 4 to 6 weeks). This is the critical window. At least two-thirds of fetal growth happens now, so energy demand climbs steeply. Sheep.extension.org notes a ewe carrying a single lamb needs roughly 50 percent more energy than in early gestation, and one carrying multiples needs about 75 percent more, at exactly the time a belly full of lambs is crowding the rumen. This is when carefully increased forage quality plus some grain earns its keep.
• Lactation. A nursing ewe, especially with twins, has the highest energy and protein needs of the whole cycle. Underfeed her now and she milks off her own back and drops condition fast. Quality forage plus grain, and plenty of water, keep her producing.

Pregnancy toxemia: the reason late-gestation feeding is not optional

Underfeeding energy in late gestation is not just a growth problem, it can be fatal. When a heavily pregnant ewe cannot eat enough energy to meet the demand of her lambs, her body mobilizes fat too fast and she develops pregnancy toxemia (also called ketosis or twin lamb disease). The MSD/Merck Veterinary Manual explains that ewes carrying multiple lambs, and those that are either too thin or too fat entering late gestation, are most at risk.

Early signs are subtle: a ewe that lags behind the flock, goes off feed, seems dull or wobbly, or presses her head against something. It progresses quickly to being unable to rise, and it is often fatal once advanced. This is an emergency, not a home-remedy situation: call your veterinarian at the first sign. The real answer is prevention, which means feeding late-gestation ewes correctly and keeping them at a sensible body condition (not letting them get over-fat early, then unable to eat enough at the end). Tracking each ewe’s condition and due dates on her profile, with a reminder set for the start of that critical late-gestation window, makes it far easier to catch a slipping animal before it is a crisis. Our sheep gestation guide covers the timeline in detail.

Water and mineral: the two things that must never run out

Water. Clean, fresh water is a nutrient. Sheep drink on the order of 1 to 4 gallons per head per day depending on size, weather, and whether they are lactating, per University of Missouri Extension. Lactating ewes and hot weather push intake to the top of that range and beyond. Dirty or frozen water depresses intake, which hurts milk production and raises the risk of urinary stones in males. Check and clean waterers regularly.

Mineral and salt. Provide a loose (not block) mineral formulated specifically for sheep, free-choice, alongside forage. Sheep struggle to get enough from hard blocks by licking, and loose mineral lets them balance what forage alone leaves short. Just remember the copper rule above: it must say sheep on the tag. Our sheep minerals guide goes into which minerals matter and why.

Keeping the feeding record straight

Feeding decisions are easier when you can see each animal’s history: what condition a ewe was in last season, when she is due, whether a wether has a history of urinary trouble, when the flock was last on grain. On Creatures you can keep a profile for every animal and log records for body condition, weights, and health notes, then set reminders for the late-gestation feed change or the next mineral check. It turns feeding from memory into a plan you can actually follow across a whole flock. You can explore the broader sheep species hub for the rest of the care picture, and if you are still naming new lambs, the sheep name generator is a lighthearted place to start.

Frequently asked questions

Can sheep eat goat feed?

No. This is the most important don’t in sheep feeding. Goat and all-stock feeds contain added copper at levels that are safe for goats but slowly poisonous to sheep, which store copper and excrete it very slowly. Feed only products labeled for sheep, and never share a mineral station between sheep and goats.

How much grain should I feed a sheep?

For most mature sheep at maintenance on good forage, none. Grain is a supplement reserved for late gestation, lactation, growing or finishing lambs, and thin animals. When you do feed it, introduce it gradually over one to two weeks, keep the amount modest and consistent, and be especially cautious with wethers and rams because of urinary calculi risk. Ask your veterinarian or extension nutritionist to help set an amount for your specific animals.

What is the best hay for sheep?

A clean, leafy grass hay or a grass-legume mix suits most sheep at maintenance. Richer alfalfa is genuinely useful for late-gestation and lactating ewes but is more than many sheep need otherwise. Whatever you choose, it must be mold-free and dust-free, and a forage test is the surest way to know its real feeding value.

Why is my sheep off feed and weak?

Many things cause it, from parasites to pregnancy toxemia to copper toxicity to grain overload, and several of them are emergencies. Going off feed in a late-gestation ewe, red or brown urine, straining to urinate, or sudden weakness all warrant a same-day call to your veterinarian rather than waiting to see if it passes.

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