What to Feed Chickens: Starter, Grower, and Layer

Author: Elliott Garber, DVM

Feed chickens a complete, age-matched formulated feed as the free-choice base of the diet, and match the feed to the bird’s stage: chick starter for chicks, a grower or developer feed after the starter, and a layer feed (commonly around 16 percent protein with added calcium) once your hens actually start laying. A good complete feed already carries the right balance of protein, energy, vitamins, and minerals, so the rest of feeding is mostly about not undoing that balance with treats and about supplying grit, calcium, and clean water on the side. This guide walks the whole progression and the few supplements that matter.

Start with a complete feed as the base

The single most useful thing to understand about chicken feeding is that a commercial complete feed is formulated to supply everything a bird needs at that life stage, in the right proportions. According to Penn State Extension and the poultry extension network, a balanced ration built around protein, energy, vitamins, and minerals is what keeps birds growing and laying well. A complete feed does that math for you.

Because the feed is already balanced, your job is mostly to buy the right stage of feed, keep it fresh and clean, and offer it free choice so birds can eat to their needs through the day. Everything else in this guide, treats, grit, and calcium, sits on top of that base without replacing it. If you get the base right, the rest is minor.

Complete feeds come in a few textures. Crumble is a coarse, broken-up form that younger birds and small breeds often handle more easily. Pellets are compressed and produce less waste because birds cannot pick through them. Mash is finely ground. All three can be complete and balanced; the texture is about preference and waste, not nutrition. Buy from a source with reasonable turnover so the feed is not sitting stale.

Match the feed to age and purpose

Chickens move through a predictable feed progression as they grow. Getting the stage right matters, especially the timing of layer feed, because a feed built for one stage can actively harm birds at another.

Chick starter

Newly hatched chicks need a high-protein starter feed. Extension guidance puts starter at roughly 18 to 20 percent protein to support fast early growth, along with the energy, fiber, vitamins, and minerals young birds need (poultry extension). Starter is usually fed for about the first 6 to 8 weeks (University of Minnesota Extension). If you are brooding chicks for the first time, our guide to raising baby chicks covers the brooder, heat, and water setup that go alongside the feed.

Grower or developer

After the starter phase, around 8 weeks of age, pullets move to a grower or developer feed. This has somewhat lower protein than starter because the rapid early growth has slowed, and it carries the young birds through until they are ready to lay (University of Minnesota Extension). The key point in this window is what you do not feed: hold off on layer feed until the birds are actually laying.

Layer feed

Once hens start laying eggs, around 20 weeks of age, switch them to a layer feed. Layer diets commonly run around 16 percent protein and carry roughly 2.5 to 3.5 percent calcium to support daily eggshell formation (poultry extension). The timing is not just a nicety. Feeding a high-calcium layer ration to young, non-laying pullets can cause bone problems or kidney damage, so wait for the eggs before you make the switch. That is why the grower stage exists at all.

If you keep birds for meat rather than eggs, the progression differs (higher-protein meat-bird rations), but for the backyard laying flock the starter to grower to layer path is the standard route. For mixed flocks with roosters, growing pullets, chicks, or hens on a laying break, a lower-calcium all-flock or grower feed with free-choice oyster shell for the active layers is the safer default, since the extra calcium in layer feed can harm birds that are not laying.

Treats, scratch, and kitchen scraps: keep them small

This is where most backyard flocks go wrong. Treats, scratch grains, and kitchen scraps are fine in moderation, but they dilute the balanced base feed if you overdo them. A widely used rule of thumb is to keep treats and scraps under roughly 10 percent of total intake. Extension sources frame the same idea in terms of time: offer only as much as the birds can finish in about 10 to 20 minutes, because overfeeding scraps means birds fill up on unbalanced food and skip the complete feed (UGA Extension).

Scratch is the biggest offender because it looks like feed. It is not. Scratch is a collection of cracked grains such as corn, with no complete balance of the nutrients a chicken needs, and it should be treated as an occasional treat rather than a meal (poultry extension). If you feed scratch, offer it in the afternoon after birds have already eaten their complete feed, and only as much as they clean up in 15 to 20 minutes.

Kitchen scraps such as leafy greens, vegetable peelings, and stale bread can add variety and trim feed costs a little, but the same limit applies: small amounts, not a substitute for the base ration. And a scraps caution that matters for safety: never feed moldy or spoiled food. Some molds produce toxins that are dangerous to birds, so anything past its prime goes in the compost, not the run.

A short list of foods to keep away from the flock: avoid feeding anything moldy or rotten, raw or dried beans, and known problem foods for poultry such as avocado (the pit and skin contain persin), and keep salty, greasy, or heavily processed human food to essentially none. When in doubt, leave it out and let the complete feed do its job. If a bird shows signs of illness after eating something questionable, call a veterinarian rather than trying to treat it at home.

Grit and calcium: the two supplements that matter

Two things a complete crumble or pellet does not fully cover on its own are grinding and, for layers, extra calcium. These are offered on the side, free choice, so birds take what they need.

Insoluble grit

Chickens have no teeth. They grind food in the gizzard using small hard stones, which is what grit provides. If your birds eat only a complete crumble or pellet and nothing else, they may not need supplemental grit. But the moment they eat anything else, scratch, whole grains, greens, scraps, or forage while free-ranging, they need insoluble grit available to grind it. Match the grit size to the age of the bird, chick-sized grit for chicks and pullets, larger grit for adults (University of Minnesota Extension). Birds with access to the ground often pick up enough coarse material on their own, but offering commercial insoluble grit free choice removes the guesswork.

Oyster shell for layers

Laying hens need a lot of calcium to build a shell on an egg most days. Layer feed supplies a baseline, but many laying flocks benefit from crushed oyster shell offered free choice in a separate feeder so higher-producing hens can top up as needed (poultry extension). Two important points: oyster shell is a soluble calcium source, not grit. It dissolves and does not grind, so it does not replace insoluble grit. Keep them in separate feeders. And because non-laying birds do not need the extra calcium, offering it free choice (rather than mixing it into the feed) lets each bird self-regulate.

For the full breakdown of when each supplement is needed and how to offer it, see our grit and supplements guide. You can read more about the laying flock generally on the chicken species page.

Water is part of the diet

Water is easy to overlook and it is arguably the most important single input. Chickens need a constant supply of fresh, clean water at all times, and they will cut back on feed and on laying quickly if water runs short or gets fouled. Check and refresh waterers daily, scrub them regularly, and in cold weather make sure the water is not frozen. In hot weather, extra clean water and shade are a genuine welfare issue; our heat stress guide covers the warm-season side.

Medicated versus non-medicated chick starter

When you buy chick starter, you will see medicated and non-medicated versions, and the difference is worth understanding. Medicated starter typically contains a coccidiostat, usually amprolium, which helps young chicks develop resistance to coccidiosis, a common and sometimes deadly intestinal parasite in brooders. Amprolium-medicated feed is available without a prescription, but check the label, because some feeds labeled “medicated” contain other additives rather than a coccidiostat (Penn State Extension).

The main decision point is vaccination. If your chicks were vaccinated against coccidiosis at the hatchery, use non-medicated feed, because the medication can interfere with the vaccine. If they were not vaccinated, medicated starter is a reasonable preventive choice, especially in warm, damp brooder conditions where coccidiosis thrives. Either way, this is a management decision, not a treatment: if chicks show signs of active coccidiosis (bloody droppings, huddling, lethargy), that is a veterinary matter, not something to self-medicate through feed. Our raising baby chicks guide covers brooder hygiene, which is the other half of coccidiosis prevention.

Keeping feed records on your flock

Feeding decisions get easier when you track them. If you keep birds on Creatures, you can log which feed each group is on and when you switched stages, so you are not guessing whether a pullet batch is still on grower or ready for layer. The health and medical records tab is a natural place to note a vaccination status (which drives the medicated-feed choice) or a diet change tied to a health issue, and you can set reminders and upcoming care for the roughly-20-week switch to layer feed so it does not slip. Getting a flock set up starts with adding an animal, and from there each stage change is just adding a record.

Frequently asked questions

When do I switch my chickens to layer feed?

When they actually start laying eggs, which is around 20 weeks of age for many breeds. Do not switch earlier just because the calendar says 20 weeks; wait for the first eggs. Feeding high-calcium layer feed to birds that are not yet laying can cause bone and kidney problems, which is why the grower stage exists.

Can I just feed my chickens kitchen scraps and scratch grain?

No. Scratch and scraps are treats, not a complete diet. Scratch is cracked grain with no balanced nutrient profile, and scraps are unpredictable. Keep both under roughly 10 percent of total intake, offered as an afternoon extra, and let a complete formulated feed be the free-choice base.

Do my chickens need grit if I feed them a complete feed?

If they eat only a complete crumble or pellet and nothing else, they may not need supplemental grit. But if they eat scratch, scraps, greens, or forage, they need insoluble grit to grind it in the gizzard. Offer it free choice, sized to the age of the bird.

Is oyster shell the same as grit?

No. Oyster shell is a soluble calcium source for eggshell formation; it dissolves and does not grind food. Grit is hard and insoluble and does the grinding. Laying hens benefit from both, offered in separate free-choice feeders.

Should I buy medicated or non-medicated chick starter?

If your chicks were vaccinated against coccidiosis, use non-medicated feed so you do not interfere with the vaccine. If they were not vaccinated, medicated starter (with amprolium) is a reasonable preventive, especially in warm, damp brooders. Signs of active illness are a veterinary matter, not a feed-only fix.

Do this next on Creatures

Whether you are dialing in flock care, hatching your first chicks, or adding to your flock, Creatures is the records, marketplace, and directory layer to do it in one place.