What to feed chickens: treats, kitchen scraps, and foods to avoid

A backyard flock will eat almost anything you hand it, which is exactly the problem. The bird that gobbles tomato hornworms and stale bread with equal enthusiasm has no instinct for what quietly harms it, so the job of deciding what to feed chickens falls to you. Get the balance right and treats earn their keep — they cut feed bills, clear the garden of pests, and give a cooped flock something to do. Get it wrong and you either dilute a carefully built ration into junk food or hand a hen something her heart cannot tolerate. This guide covers the supplemental side of feeding, organized as one rule and two lists: the 90/10 split that keeps treats in check, the safe scraps a flock loves, and the 5 or 6 foods chickens should never eat, plus the calcium that drives laying and what to feed in winter. If you are still assembling the flock, our guide to starting a small backyard flock sets the complete-feed baseline this piece builds on.

Start with complete feed, then add the 10%

Before any treat enters the picture, one rule anchors everything: a balanced complete feed is the diet, and everything else is a garnish. The Merck Veterinary Manual states it without hedging — “although foraging behavior might be desired, birds should receive most of their diet from a balanced, nutritionally complete ration.” That ration is formulated to hit the protein, vitamins, and minerals a chicken needs, which is why it should be at least 90% of the diet; scraps and grains are not balanced and cannot carry that load. So the answer to what do i feed a chicken, at its core, is a complete feed sized to the bird’s life stage, with treats layered on top in strict moderation.

The discipline that keeps treats from doing harm is the 90/10 rule. Purina Animal Nutrition puts it plainly: “provide complete feed for at least 90 percent of the bird’s diet. The remaining 10 percent can be filled with chicken treats.” The logic is dilution. Every handful of low-protein scratch or watermelon rind displaces feed the bird would otherwise eat, and the more grain a flock fills up on, the less of the complete ration it touches. University of Florida Extension makes the same point about scratch and cracked corn — it “does not provide the adequate protein and other nutrients needed by your birds and might be thought of as a treat rather than a staple,” and “birds consuming more grains will eat less of the complete nutrition provided by feed, reducing the overall nutritional value of the diet.”

The 20-minute rule of thumb

The 90/10 split is easy to say and hard to eyeball, so extension educators offer a kitchen-timer version. The eXtension small-flock guidance is that “the total supplementation of table scraps and scratch grains should be no more than chickens can finish in 20 minutes.” Feed treats in the afternoon, after the birds have already eaten their complete feed, and put out only what they will clean up in 15 to 20 minutes. That single habit does most of the work of staying near 10%.

A useful mental image comes from the same source: “scratch grains are like french fries — chickens that eat too many scratch grains have less of an appetite for more nutritious feed.” Alabama Extension reaches for dessert instead, warning that if you give hens “too much ‘ice cream’ in the form of scratch grains, treats, or kitchen scraps, their egg production is likely to suffer.” French fries or ice cream, the lesson is the same across all 10% of the treat budget: treats are the fun part of the plate, never the meal.

Safe treats and kitchen scraps chickens love

Within that 10%, chickens are happy omnivores, and a surprising share of what to feed chickens naturally already passes through your kitchen. Purina’s list of safe options is reassuringly ordinary: “vegetables: lettuce, beets, broccoli, carrots, kale, swiss chard, squash, pumpkins and cucumbers,” plus fruit — “watermelon, strawberries, and blueberries make healthy snacks for chickens.” Add cooked grains, plain leftover rice or oats, and the odd handful of mealworms, and you have covered nearly every treat a flock needs.

A few categories of scraps are worth calling out because they pull double duty as treats and as protein or enrichment, and each still sits inside that 10% ceiling:

• Leafy greens and vegetable trimmings — kale, chard, lettuce ends, carrot tops, broccoli stems. Tear or chop them so birds can manage the pieces.
• Fruit, in moderation — melon rinds with clinging flesh, berries, apple flesh (skip the seeds in quantity). Fruit is sugary, so it counts firmly inside the 10%.
• Cooked vegetables and grains — cooked squash, pumpkin, plain rice, oatmeal, and pasta are all fine cooked and unseasoned.
• Garden pests — Japanese beetles, hornworms, slugs, and grubs are free, high-protein treats, which is half the reason a flock earns its place in a vegetable garden.

The honest caveat is that scraps vary wildly in nutrition, so they cannot replace feed. A pile of watermelon rind is more than 90% water; a bowl of bread is mostly starch. That is why the bulk of the diet — that same 90% — stays as complete feed and the scraps stay a treat, the principle that answers what feed to feed chickens for nearly every backyard keeper.

What not to feed chickens

Those harmless kitchen scraps have a dangerous cousin: a handful of foods cross the line from low-value to genuinely toxic, and these 5 or 6 are worth memorizing before someone empties the compost bowl into the run. Most scraps are fine, but the question of what not to feed chickens has real toxins behind it, not folklore.

The toxic short list

University of Florida Extension publishes a blunt do-not-feed list for backyard flocks, running to 6 categories. In their words: “never feed the following to your flock: raw green potato peels; nightshades such as rhubarb, pepper, potato, eggplant, or tomato leaves; raw, dried, or undercooked beans; avocado skin and pit; candy, chocolate, sugar; alcohol and tobacco.” Each item on that list has a mechanism, and the toxins are well documented:

• Avocado (skin and pit) — the toxic principle is persin. The Merck Veterinary Manual notes that “ingestion of avocado fruit, leaves, stems, and seeds has been associated with toxicosis in animals; leaves are the most toxic part,” and that affected birds show “lethargy, dyspnea, anorexia, subcutaneous edema of the neck and pectoral regions, and death” within 24 to 48 hours. Chickens are listed among the susceptible species, though Merck adds that “chickens and turkeys seem more resistant” than caged birds — a reason for caution, not a green light.
• Chocolate and caffeine — both contain methylxanthines. Per Merck, “the primary toxic principles in chocolate are the methylxanthines theobromine and caffeine,” which “competitively inhibit cellular adenosine receptors, resulting in CNS stimulation, diuresis, and tachycardia.” Deaths have been reported in animals eating cocoa byproducts. Keep coffee grounds, chocolate, and candy out of the run.
• Raw or dried beans — uncooked beans “can be harmful because they contain a compound known as hemagglutinin,” per Purina. Beans must be thoroughly cooked before they are safe; raw or dried is a hard no.
• Green potato and nightshade leaves — the green on a potato signals solanine. Michigan State University Extension explains that potatoes, tomatoes, and eggplant “are members of the nightshade family,” and that the green part “contains solanine, which eaten in great quantities can cause illness.” Skip green or sprouting potato peels and the leaves of nightshade plants.
• Moldy, rotten, or very salty food — Purina warns that “moldy, rotten foods and very salty foods can result in excessively wet feces and may be toxic.” Mold can carry mycotoxins, and a small bird has little tolerance for salt, so compost that has turned belongs in the heap, not the feeder.

When in doubt, leave it out

Two practical rules cover the gray areas. First, never feed a chicken anything moldy, spoiled, heavily salted, greasy, or sugary, even if the core food would be safe fresh — the seasoning and spoilage are the hazard. Second, when a food is not clearly on the safe list, leave it out rather than gambling; the 10% treat budget is too small to spend on a maybe. This is the same caution that protects the youngest birds, which is why the chick-starter stage keeps treats near zero — covered in our guide to raising chickens for eggs, which carries the diet through laying.

What to feed chickens to lay eggs

Once hens are in lay, the feeding question shifts from protein to minerals, and the answer to what to feed chickens to make them lay eggs is less about treats than about calcium. A laying hen pours an extraordinary amount of calcium into her shells: the eggshell is, per Alabama Extension, “composed of around 96 percent calcium carbonate,” and a hen builds one almost every day. The feed has to keep up.

That is why a layer ration is built differently from a grower feed. The Merck Veterinary Manual notes that “laying birds require 3.5 to 6% calcium because of the nutritional demand of egg laying,” many times the roughly 1% a growing pullet needs. Alabama Extension recommends “a layer diet with around 18 percent crude protein to maintain good egg production,” and the eXtension figure for the calcium in a typical laying mash is “2.5% to 3.5% calcium,” against “only 1.2% calcium” for growing chickens. So the short answer to what to feed laying chickens is a complete layer feed — protein in the high teens, calcium near 3% — fed as the staple, with treats kept inside that same 10%.

Oyster shell, free-choice

Whether to add oyster shell on top of a layer feed comes down to shell quality. The eXtension guidance is that “it may also be necessary to supplement the diet of laying hens with ground oyster shell on a free-choice basis,” because a hen laying close to 1 egg a day sometimes needs more calcium than the feed alone provides. Alabama Extension adds an honest counterpoint: “if you are feeding a high-quality complete layer diet, supplementing a layer flock with oyster shell is probably unnecessary.” Both can be true. The clean rule is to offer crushed oyster shell in a separate dish, free-choice, and let the hens self-regulate — they will eat more when they need it and ignore it when they do not. Watch the shells: thin or easily cracked shells are the signal to make sure that calcium is on offer.

Feeding through a molt

Once a year, usually in autumn, hens drop and regrow their feathers in a molt, and laying typically pauses while they do. Feathers are mostly protein, so the bird’s needs rise just as the eggs stop. The standing extension advice is that “chickens have a high protein and calcium requirement during molting,” and many keepers shift a molting flock onto a slightly higher-protein ration — a feather-fixer or game-bird feed in the low 20s percent protein — until the new plumage is in. A molt runs “about 10 to 12 weeks to complete,” so this is a season-long adjustment, not a one-week fix. Scratch and treats matter even less here; the protein is doing the heavy lifting.

What to feed chickens in winter

That protein matters even more once the weather turns, but cold changes the whole math — and by as much as 25%. A bird burns extra calories to stay warm, so the question of what to feed chickens in winter is mostly about energy and keeping the basics flowing when everything wants to freeze.

The headline figure comes from the University of Minnesota Extension: “your flock’s feed intake may increase up to 25 percent during cold weather.” The practical response is simple — “be sure to have extra feed on hand and top off feeders routinely,” and keep the same balanced ration rather than switching to something exotic. The extra appetite is the bird telling you it needs more fuel, not a different diet.

Scratch grains earn a special winter role here. As UMN notes, “digestion of scratch grains also produces heat, so providing scratch grains before roosting can help chickens stay warm on cold nights.” A handful of cracked corn or scratch tossed into the bedding in late afternoon gives the flock a warming meal to digest overnight and something to scratch for during short, boring days. It still counts inside the 10% treat budget — but winter is the one season where leaning toward the top of that budget makes sense.

Foraging and free-range: a supplement, not a diet

Those refills and feeders still matter in summer too, because a flock on grass only looks like it is feeding itself — a picture that flatters foraging more than the science does. Birds with outdoor access do pick up greens, seeds, and insects, but research summarized by extension shows that only a small portion of a bird’s nutritional needs is actually met by foraging, and that forage and scraps can displace the complete feed that carries the real nutrition. So the complete ration still stays on offer 100% of the time, even for a free-ranging flock.

That ration matters because pasture only does part of the job. Young, tender greens are a genuine supplement, while old, fibrous growth is poorly digested and worth little; birds on pasture also grow more slowly than the same breed on complete feed alone. For keepers who want to lean into forage, designing the run around what chickens actually eat pays off — and the broader playbook for a feed-aware flock lives in our library of flock guides. Foraging is a bonus on top of the 90%, never a substitute for it.

Grit, the silent partner

Those foraged greens and treats come with one cost: a chicken has no teeth, so it needs grit to grind anything tougher than a fine crumble. The eXtension rule is direct — “when feeding scratch grains to chickens, it is also important to provide grit to help the chickens grind and digest the grains properly,” and “grit is important for breaking down the grass chickens consume.” A bird on nothing but complete feed does not need it, but the moment grass, seeds, or scraps make up any part of the diet, grit does. Offer insoluble granite grit free-choice in its own dish, 1 of the 2 mineral dishes a laying flock should have — grit for grinding, oyster shell for calcium, and never the two confused.

A safe-versus-avoid cheat sheet

Those mineral dishes, the 90/10 split, and the toxic list all come together on one card. The table below sorts the common foods into a safe column — fine inside the 10% treat budget — and a never-feed column to keep out of the run entirely.

Chicken Diet Composition: The 90/10 Rule90% Complete Feed10% TreatsA complete feed provides balanced nutrition essential for health.Treats and kitchen scraps are supplements, not dietary staples.

A flock fed off the left column inside the 10% line, with a complete feed for the other 90% and grit and water always available, is fed correctly. The right column is short on purpose — those are the foods worth a firm habit of keeping away from the run.

Feeding across the year

Treats and supplements are not static — what a flock needs shifts with laying, molt, and the four seasons. The timeline below maps the supplemental feeding year onto the moments that matter, from spring lay-up through the autumn molt and into winter, when intake can climb 25%.

The takeaway

Those foods and habits boil down to a sticky note. Make a complete feed at least 90% of the diet and keep treats and kitchen scraps to the other 10%, capped at what the flock clears in 15 to 20 minutes. Lean on safe, ordinary scraps — leafy greens, vegetables, fruit, cooked grains, garden pests — and keep the genuinely toxic short list out of the run: avocado, chocolate and caffeine, raw or dried beans, green potato and nightshade leaves, and anything moldy or salty. For laying hens, let calcium do the work with a layer feed near 3% calcium and oyster shell free-choice if shells thin; through a molt, raise the protein. In winter, expect intake to rise about 25% and use scratch before roost for warmth, with water kept unfrozen at all costs. And treat foraging as the bonus it is, never the diet. Do that, and a flock will reward you with eggs, pest control, and very little drama at the feeder.