Chicks start on starter feed from day one, switch to grower feed around 8 weeks of age, and move to layer feed between 16 and 20 weeks, once they begin laying eggs. Each stage has a different protein and calcium balance designed for what a bird’s body needs at that point in its life. Getting the timing right matters more than most new flock owners realize, because feeding the wrong formula at the wrong age can cause real health problems.
Starter Feed: Hatch Through 8 Weeks
Chick starter feed contains 18 to 20% protein, the highest of any stage. That protein fuels the rapid muscle, bone, and feather growth happening in the first two months of life. The feed comes as fine crumbles that tiny beaks can manage easily, and chicks should have free access to it around the clock along with clean water.
If you’re using medicated starter, it contains amprolium, which helps chicks build resistance to coccidiosis, a common intestinal parasite. One important note: if your chicks were vaccinated for coccidiosis at the hatchery, do not feed medicated starter for at least 28 days after vaccination. The amprolium can interfere with the vaccine’s ability to build immunity. If your chicks weren’t vaccinated, medicated starter is a reasonable precaution, especially for first-time flock owners.
Grower Feed: 8 to 16 Weeks
At 8 weeks, switch to grower feed. The protein drops slightly to 15 to 18%, which supports steady growth without pushing birds too fast. Excessive growth spurts during this adolescent phase can lead to leg problems and joint issues, so the lower protein level is intentional. The pellet or crumble size is also slightly larger, matching the birds’ growing beaks.
Many feed brands sell a combined “starter/grower” formula at around 18% protein. This is perfectly fine to use from hatch all the way through 16 weeks if you’d rather not buy two separate bags, especially for a small backyard flock. The key thing is to avoid layer feed during this period. Layer feed contains 3 to 4% calcium to support eggshell production, and that level of calcium can damage the kidneys and parathyroid glands of young, immature birds that aren’t producing eggs yet.
Layer Feed: 16 to 20 Weeks
The switch to layer feed is driven by biology, not a fixed date on the calendar. Layer feed becomes appropriate when your pullets start laying, which typically happens between 16 and 20 weeks depending on the breed. Some breeds start closer to 18 or even 22 weeks, so watch your birds rather than counting days.
Several physical signs tell you a pullet is approaching her first egg. Her comb and wattles will grow larger and turn a deeper, redder color. Her pelvic bones, the two small bones on either side of the vent, will start to widen and separate to make room for eggs to pass through. Her abdomen will feel softer and fuller. These changes vary between breeds, but if you’re seeing red combs and wider pelvic spacing, the transition to layer feed is near.
Layer feed contains 16 to 18% protein along with that elevated calcium level (3 to 4%) that hens need to form strong eggshells every day. Without enough calcium, hens pull it from their own bones, which weakens their skeleton over time.
How to Transition Between Feeds
Chickens have sensitive digestive systems, and an abrupt feed change can cause stress, loose droppings, or a temporary drop in eating. A gradual transition over three to four weeks works best, especially when moving to layer feed:
- Week 1: 75% current feed, 25% new feed
- Week 2: 50% current feed, 50% new feed
- Week 3: 25% current feed, 75% new feed
- Week 4: 100% new feed
The starter-to-grower transition is usually less disruptive since the formulas are similar, and many birds handle it with just a week of mixing. The grower-to-layer switch deserves the full gradual approach because the calcium content changes significantly.
Meat Birds Follow a Faster Schedule
If you’re raising broilers rather than laying hens, the timeline compresses dramatically. Meat breeds grow much faster and are typically processed between 6 and 10 weeks of age. They move from a high-protein prestarter in weeks 1 and 2, to a starter or grower around weeks 3 through 5, and then to a finisher feed from week 6 until processing day. The protein stays high throughout because the goal is rapid, efficient muscle development rather than long-term health. Layer feed is never part of the equation for meat birds.
When to Introduce Grit
If your chicks eat only commercial crumbles, they don’t technically need grit, because the feed dissolves easily. But the moment you introduce treats, scratch grains, grass, or any whole food, grit becomes essential. Chickens don’t have teeth. They rely on small stones held in their gizzard to grind food mechanically.
You can introduce chick-sized grit as early as day 3. For the first two days, sprinkle a small amount over their feed so they learn to distinguish it from food. After that, offer it free-choice in a separate dish. Use fine “chick grit” for young birds and switch to standard poultry grit as they grow. Layer hens also benefit from oyster shell offered free-choice alongside their feed, which provides an extra calcium source beyond what’s in the layer ration. Offer oyster shell only once birds are in lay, not before.
Mixed-Age or Mixed-Flock Situations
Things get trickier when you have birds of different ages or a mix of hens and roosters eating together. Roosters don’t need the extra calcium in layer feed, and young pullets shouldn’t have it. The simplest solution is to feed the entire flock a grower or “all-flock” formula (typically 16 to 18% protein, low calcium) and set out a separate dish of oyster shell. Laying hens will eat the oyster shell as their bodies demand it, while roosters and younger birds will mostly ignore it. This approach keeps everyone on an appropriate diet without needing to separate birds at feeding time.