When to Switch Chicks to Layer Feed: Feeding Chickens at Every Age

Chickens at different stages of development require different feed formulations.

Many people are unsure when and why to transition pullets that have not yet begun laying to a layer feed, or why it is important not to make this switch too early.

With chick season approaching, this information may be helpful for new chicken owners.

One of the most common questions new chicken owners ask is, “When should I switch my chicks from starter feed to layer feed?” Switching too early can cause serious health problems for growing birds.

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Starter Feed – Day 1 to 18 Weeks (Chicks)

Starter feed contains the highest percentage of protein (around 20%) a layer will ever consume, which makes sense given the rapid growth chicks experience in their first few months.

Starter feed is available in medicated and non-medicated varieties.

Medicated feed contains amprolium, which helps prevent the progression of coccidiosis, a common and potentially deadly intestinal disease spread through fecal matter.

Chicks that have received the coccidiosis vaccine should NOT be fed medicated starter, because amprolium interferes with the vaccine and can make it ineffective.

When conditions become overcrowded, dirty, wet, and warm from the heat source, coccidiosis can thrive with deadly consequences.

Chickens gradually build natural immunity to the organisms that cause coccidiosis, whether medicated feed is used or not. Providing chicks with a clean, dry environment helps them safely develop that immunity until they are ready to move to the coop.

As for treats, I do not recommend offering any to chicks. Their bodies are growing rapidly, and treats replace valuable nutrition from starter feed that they need for proper development.

Layer Feed – 18 Weeks

Pullets should be transitioned to layer feed at around 18 weeks of age.

Layer feed must not be fed to chickens younger than 18 weeks unless they have begun laying eggs. Layer feed contains added calcium which, if fed too early, can permanently damage the kidneys, reduce lifetime egg production, and shorten a chicken’s lifespan.

Layer feed is available in mash, crumble, and pellets and typically contains 16–18% protein along with added calcium for strong bones and eggshell production.

If hens do not receive enough dietary calcium, they will pull calcium from their own bones to produce eggshells. Over time this can lead to weak bones and osteoporosis.

Supplemental Calcium

Layer feed contains crushed limestone, which provides a quick release of calcium.

Crushed oyster shell, which releases calcium slowly, should be offered free-choice in a separate dish rather than mixed with the feed. Each hen has different calcium needs and will consume the amount she requires.

Don’t be concerned if the oyster shell dish doesn’t seem to empty quickly. Hens that need extra calcium often take a piece or two before going to roost, since eggshell formation happens overnight.

During the day they receive calcium from their feed, but overnight—when they are not eating—some hens require additional calcium.

Oyster shell works somewhat like a rock in a dryer, tumbling in the gizzard and slowly dissolving overnight while the eggshell forms.

You can purchase oyster shell at most poultry feed stores.

Do Not Feed Eggshells Back to Chickens

Eggshells provide quick-release calcium, similar to the limestone already present in feed.

Because chickens can absorb only a limited amount of calcium at once, excess calcium must be expelled through the kidneys, increasing the risk of kidney strain or damage.

Feeding Different Age Groups Together

“Chicken math” is real, and many backyard flocks end up with birds of different ages.

The best solution is to feed starter or grower feed and provide oyster shell free-choice in a separate dish.

The extra protein in starter or grower feed will not harm adult birds, but the extra calcium in layer feed can damage the kidneys of growing birds.

Non-Medicated Starter/Grower Feed

If you do not have older birds in your flock, it is not necessary to switch from medicated starter to non-medicated starter/grower feed.

Chicks can remain on medicated starter right up until the transition to layer feed at 18 weeks. The amprolium helps protect them while their immune system develops.

Side Note – Why We Do Not Feed Layer Mash

We do not feed layer mash.

Mash contains pieces of different sizes and colors, and chickens eat largely based on visual cues. They often pick out the largest or brightest pieces, leaving the rest behind.

Although mash is nutritionally complete when packaged, selective eating means birds may miss important nutrients, meaning they eat with their eyes, which can lead to poor health, reduced egg production, and weakened immunity.

Why We Do Not Feed Treats

We do not give treats to our chicks, pullets, or breeding flock.

That means no fruits, vegetables, mealworms, scratch, cracked corn, watermelon, or other extras.

These foods dilute the carefully balanced nutrition in commercial poultry feed and can lead to long-term nutritional imbalances.

If chickens are kept as pets for many years, maintaining proper nutrition becomes especially important for their long-term health and lifespan.

Our Feed Choice

Our poultry feed of choice is:

• Purina Medicated Starter/Grower Crumbles for chicks and grow-outs

• Purina Layer Pellets for birds over 18 weeks

Purina poultry feed is produced by Land O’Lakes, not Nestlé (which makes Purina pet foods).

We choose Purina for two main reasons:

1. It is a well-established and respected feed company. Poultry nutrition is a science, not just a recipe, and long-standing companies invest heavily in research.

2. They have poultry nutritionists available if customers have questions about their feed—something few companies offer.

   
   

Local Feed Stores That Carry Purina

If you live in the general area of our ranch, Purina feed is available at:

1. Madoc Farm Supply

2. Campbellford Farm Supply

3. Warkworth Farm Supply

4. TCO Agromart – Selby/Napanee

5. Picton Farm Supply

   
   

We do not receive any profit or commission from Purina. Our goal is simply to share what we have learned about poultry nutrition through our own research and experience.

Proper nutrition of our breeding stock is essential for producing healthy hatching eggs, chicks, and grow-out pullets.

Feeders and Oyster Shell Dispenser

In the photo at the top of this blog you can see our Grandpa’s Feeder, which holds about 40 lbs of feed (roughly ¾ of a bag).

If you are looking to reduce feed waste from rodents or chickens, this style of feeder works extremely well.

There are also more budget-friendly metal feeders available with slightly lighter metal that still perform well. We use these with our grow-out pullets.

You will also see our oyster shell container, which is simply a plastic wild bird feeder hung inside the run.

You can find something similar at the Dollar Store for around $5, and it only needs to be refilled two or three times per year.

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We hope this information was helpful.

If you have any questions or comments, feel free to contact us directly or leave them in the comments below.