Say you keep a horse and a few hens, and the oat bin is right there in the barn. Can the flock have some? Yes. Plain oats are a grain chickens can eat, and poultry researchers have put them in hen diets for years. But “oats for horses” can mean more than one thing. And the bag you’re scooping from may not be plain oats at all.
So I read 10 sources for this page, mostly poultry extension sheets, plus a horse feed guide and three chapters of the Merck Veterinary Manual (you’ll find them all at the bottom). Where they agree, you get one line. Where they don’t, you get both, and the one I’d go with. If you’re checking a different food, our free Can Chickens Eat It? checker has the rest.
The short version.
- Plain oats are fine for laying hens as a treat, whole or rolled.
- Sweet feed and pellets are horse rations, and so are complete feeds. Read the tag before a hen gets any.
- About 2 tablespoons of whole oats a hen a day is the most, or 3 of rolled oats. And that covers all her treats added together.
- Scatter oats on the ground. Don’t mix them into the layer feed.
- Dusty or musty oats go in the trash, and so do damp ones.
- The bigger danger runs the other way: some chicken feeds carry drugs that can kill a horse.
Yes, Hens Can Eat Horse Oats. Here’s the Fine Print
Oats aren’t new to poultry. But you won’t find them making up much of a hen’s diet, either. Dr. Jacquie Jacob’s article on oats for the University of Kentucky and extension.org says they were “used sparingly” in the past. There are two reasons. Oats carry a lot of fiber, and they carry beta-glucans, which the article calls “anti-nutritional factors that reduce nutrient availability”.
Kentucky’s poultry nutrition page puts it more bluntly. “Oat grains are composed of about 20% hulls, resulting in a high fiber/low energy grain.” And the beta-glucans “can cause digestive problems and sticky litter when fed to poultry”. The hull share isn’t fixed, either. The extension.org article says it can run anywhere from 20% to 45% of the grain, so one sack of oats isn’t the same as the next.
None of that makes oats bad for your hens. What I took from it is that they’re filler. “Poultry are not able to digest fiber very well,” the extension.org article says. So a crop full of oats is a crop full of something a lot less complete than her layer feed. That’s the fine print, and the rest of this page is about how you live with it.
What’s Actually in the Horse’s Bin?
Before a hen gets a scoop, look at what you’re scooping. The horse feed guide on extension.org calls oats “the most popular and safest grain to feed to horses”. It says they “can be fed whole or processed”, and the processing means crimping or rolling the kernel, or crushing it. Any of those is still just oats, and I’d give any of them to a hen.
But a lot of what sits in a horse’s feed room isn’t plain oats. Nebraska Extension’s guide to reading a horse feed tag (G1403, by Kathy P. Anderson) sorts horse feeds into four kinds:
- Textured concentrates, which are the sweet feeds: grains mixed with molasses.
- Processed concentrates, which come as pellets or extruded feed.
- Complete feeds, with the forage already mixed in.
- Supplements.
You’ll usually know a sweet feed by the molasses. The grains in it can be whole or processed, the guide says. And it’s often fortified “to supplement the forage portion of the diet”. That last part is the one to notice. A sweet feed is built to go with a horse’s hay. It isn’t built for a hen.
No poultry source I read says a peck of sweet feed hurts a hen. But none of them recommends it, either, so I’d leave it to the horse. And even a fortified horse feed isn’t a layer feed. The sample tag in Nebraska’s guide lists calcium at a maximum of 1.5%. Alabama Extension puts a laying hen’s diet at 3% to 4% calcium.
So read the tag. Nebraska says every bag of commercial feed “should have a tag stitched to the bottom”. If the tag says plain oats, go ahead. If you see molasses or a premix on it, or any drug, it’s a horse’s ration. And your flock already has one of its own.
What Oats Give a Hen, and What They Don’t
Here are the average numbers you’ll find for oats in the extension.org article. They come from the Feedstuffs ingredient table by Batal and Dale of the University of Georgia.
- Crude protein: 11.0%.
- Crude fat: 4.0%. Oats “contain more oil than other cereals,” the article says.
- Crude fiber: 10.5%.
- Calcium: 0.10%.
- Total phosphorus: 0.25%.
Now hold those up against the layer feed in your feeder. Alabama Extension’s table for laying hens asks for 16% protein or more and 3% to 4% calcium. So gram for gram, a layer feed carries 30 to 40 times the calcium oats do (that’s my arithmetic). Merck’s figure for laying birds is 3.5% to 6% calcium, which makes the gap even wider.
Calcium is the one you’ll see in the egg. Merck says a typical egg takes about 2 grams of calcium from the diet. Laying hens that don’t get enough “draw calcium from their bones,” and you get thin shells. So no, oats don’t make strong eggshells (the old version of this page said they did). Your layer feed and a dish of oyster shell do that.
There’s one place oats do earn their keep. The extension.org article says oats suit pullet developer and breeder diets. Oats in replacement pullets’ diets have been shown “to reduce mortality and cannibalism”. And low levels of oat hulls, about 3% of the diet during rearing, cut feather pecking in laying hens. But that’s oats measured into a balanced ration by a nutritionist. It isn’t you dumping a scoop from the horse bin on top of the feeder, and I wouldn’t read it that way.
How Much? 2 or 3 Tablespoons a Hen, at Most
No source I read gives you an oat number for hens. What they give you is a treat rule. Colorado State Extension says “Treats should make up no more than 10% of their daily diet.” And Alabama says a laying hen eats 100 to 150 grams of feed a day, roughly a quarter of a pound.
Put those two together and a hen’s whole treat allowance is 10 to 15 grams a day. Here’s what that looks like in oats. It’s my arithmetic, from the bushel weights in the horse guide and USDA’s 81 grams to a cup of rolled oats.
- Heavy whole oats (U.S. No. 1, 36 pounds a bushel): about 1½ to 2 tablespoons a hen.
- Light whole oats (U.S. No. 4, about 27 pounds a bushel): about 2 to 3 tablespoons a hen.
- Rolled oats from your kitchen: about 2 to 3 tablespoons a hen.
- For six hens: a little over half a cup to three-quarters of a cup of heavy whole oats. Or about three-quarters of a cup to a cup of rolled oats.
And that’s the ceiling for every treat she gets that day, not for oats alone. If you also hand out scraps or a slice of watermelon, the oats shrink to fit. Our Chicken Feed Calculator works out the feed side for any flock size.
How you feed them matters as much as how much. Alabama is clear about it: “avoid mixing scratch grains with your complete feed. This only dilutes the nutrients your birds need.” Merck lists the same thing among the common problems in backyard flocks, the “dilution of balanced and nutritionally complete rations with scratch or supplemental feed”. Oats tossed to hens do the same job as scratch, so I’d follow the same rule. Scatter them on the ground, away from the feeder, and leave the layer feed alone.
Colorado State adds a time limit. Don’t feed more than the birds can eat in 5 to 10 minutes, the guide says, “to not attract nuisance animals”. I’d add that grain you leave lying in the run overnight is an open invitation to whatever comes around after dark.
If you grow your own oats, Colorado State has a nicer idea. Oats and wheat “can be threshed or left on the sheaf,” and you can hang the sheaf from the coop rafters where the hens can reach it. The guide says it gives them “an activity as well as feed”. It also warns that grain fed this way makes it harder to tell whether they’re getting enough protein. So count the sheaf as treats, too.
Whole Oats and Grit: Where Two Guides Split
Here’s where the guides don’t agree, at least on the surface. Alabama Extension says the idea that chickens need grit is “untrue if the feed being provided is already ground (which all commercial feeds are)”. Birds that eat whole grains and seeds need grit, it says. Then it adds: “Backyard chicken flocks do not.”
Colorado State goes the other way. “Ensure your birds have free access to grit and a calcium source like oyster shell or eggshells.” Birds that free range “will pick up their own grit,” it says, but a limited run needs a grit source.
But when I read them side by side, they’re closer than they look. Both say a bird eating whole grain needs grit. Alabama is talking about hens on ground commercial feed, and it says so. Colorado State’s page also covers flocks that get whole grain, like those oat sheaves. And whole oats with the hull still on are whole grain.
So here’s what I’d do. If your hens free range, they’ll find their own grit (Colorado State says as much). If they live in a run and you’re adding whole oats, put out a dish of grit next to the oyster shell. Rolled or crimped oats are already broken open. But if they get them often, I’d keep the grit out anyway.
Musty or Dusty Oats Go in the Trash
The horse guide has the best quick checks I found for a bag of oats. And you can use them just as well for the flock’s share:
- Dust: “Dust in oats indicates that the oats are old and may be of lesser quality.” To check, pour some into a can and back into the sack, and watch for a cloud.
- Smell: “A musty smell indicates that the oats have been stored with too much moisture and will spoil.”
- Weight: the top grade is the heavy one. U.S. No. 1 oats weigh 36 pounds a bushel, and No. 4 about 27 pounds.
Mold is the real worry, and not just for the horse. Merck’s chapter on mycotoxins in poultry says these mold toxins can get into grain “before harvest or after harvest during transport or storage”. Once they’re in, they’re “chemically stable and persist”, right through into finished feed. So you can’t sift them out. Merck’s answer is to remove the source and replace the contaminated feed.
Storage is where you do have a say. Merck notes that “Temperature extremes cause moisture condensation and migration in bins”. Its backyard poultry chapter says feed should be stored “in a dry, cool area” to prevent fungal growth. I’d check the bottom of a barn bin after a long winter for exactly that reason. And Colorado State’s scrap rule says nothing moldy for the flock. So if the horse’s oats have gone off, they’re off for the hens too. They go in the trash, not the coop.
The Other Way Round: Keep the Horse Out of the Chicken Feed
If you keep both animals, this is the part I’d tape to the feed room door. Some chicken feeds are medicated, and some of those drugs are deadly to horses.
Kentucky’s poultry nutrition page lists the coccidiostats that “are sometimes added to feed”. Among them are monensin (Coban) and lasalocid (Avatec, Bovatec). Salinomycin is on the list too. Those are ionophores. Merck’s chapter on ionophores says they “are approved only as medicated feed additives in the US”. Monensin and lasalocid are approved in chickens, it says. So are salinomycin and narasin.
Horses are among the animals Merck calls “particularly sensitive”. The median lethal dose of monensin for a horse is 2–3 mg/kg, against 20–80 mg/kg for cattle. The causes Merck lists include “misuse in a nontarget species” and “accidental ingestion”, and a horse in the chicken feed is exactly that. A high dose can bring weakness and colic, with profuse sweating. It can end in sudden death. And Merck says “There are no specific treatments or antidotes”.
So read your chicken feed’s tag too. If it’s medicated, find the drug’s name on it. I’d store medicated feed where the horse can’t reach it, and you should never pour it in the horse’s tub. Our page on medicated vs non-medicated chick starter goes into what’s in a chick starter bag. If your horse ever gets into medicated feed, call your vet right away. Don’t wait for signs.
That’s the whole of it, as I read the sources. Plain oats are a fine treat in small amounts. And the horse’s bin is worth reading before you share it. If cheese is next on your list, here’s that one.
Updated October 2026: rewritten from the sources below and checked line by line. The old version told stories about one keeper’s own farm. Three named hens fought over oats, and feeding tests cut egg laying by a quarter in a week. Those are gone. So are the health claims no source here backs, from fewer colds and mites to brighter feathers. It said the calcium in oats makes strong eggshells, and it told you to mix a cup of oats into the feed or sweeten them with molasses. It gave an oat share of the diet and a feeding schedule. It also named a storage bin and gave tips for horses. And its four illustrations are now real photos, each one credited under it.
Sources
- Small and Backyard Poultry (extension.org): Oats in Poultry Diets (Dr. Jacquie Jacob, University of Kentucky; nutrient figures from the Feedstuffs Ingredient Analysis Table 2016, Batal and Dale).
- University of Kentucky, Department of Animal and Food Sciences: Poultry Nutrition (Jacqueline Jacob).
- Horses (extension.org): Grains for Horses and Their Characteristics (January 2020).
- University of Nebraska-Lincoln Extension: Basics of Feeding Horses: Reading the Feed Tag (G1403; Kathy P. Anderson, revised December 2007).
- Merck Veterinary Manual: Ionophores Use in Animals (Melissa A. Mercer, DVM, PhD; reviewed September 2022, updated September 2025).
- Merck Veterinary Manual: Mycotoxicoses in Poultry (Dulmelis Sandu, DVM; reviewed December 2023).
- Merck Veterinary Manual: Management of Backyard Poultry (Yuko Sato, DVM; reviewed November 2024).
- Colorado State University Extension: Raising Poultry the Organic Way: Disease Control and Feeding (Howard Enos; December 2019, reviewed August 2025).
- Alabama Cooperative Extension System: Feeding the Laying Hen (ANR-2913, Backyard and Small Poultry Flock Management Series; August 2022).
- USDA FoodData Central: Cereals, oats, regular and quick, not fortified, dry (SR Legacy 173904; the 81-gram cup).
Sources checked October 26, 2026. The spoon and cup measures are my arithmetic from these sources, and so is the calcium comparison. We aren’t vets. If a horse gets into medicated chicken feed, or a hen stops eating, call a vet who sees that animal.
Related read: How to Raise Chickens for Eggs — Instant PDF download. Secure checkout by Stripe
