Grower feed is a lower-calcium, moderate-protein ration for chickens from about 6 weeks of age until they start laying.
If you’ve raised chicks through the fragile early weeks, you know starter feed does a specific job. Grower feed is the bridge ration that carries young birds from that rapid-growth phase into adulthood. The switch matters because growing chickens need steady protein for muscle and skeletal development, but they don’t need the high calcium that laying hens require for eggshell production. Feeding the wrong ration at the wrong time can cause real problems down the road.
What’s Actually In Grower Feed?
Grower feed is formulated with roughly 15–16% protein according to Oregon State University Extension, though many commercial brands sell grower rations at 16–18%. The defining characteristic is what’s missing: calcium. Layer feed carries elevated calcium specifically for eggshell formation, and feeding it to immature birds can stress their kidneys and cause other health issues.
The feed typically comes as crumble or pellets, which encourages slower eating than the fine mash of starter feed. That texture shift also helps birds transition to the larger particle sizes they’ll see in layer rations later.
Oregon State Extension notes that grower and developer feeds are virtually interchangeable. Developer feed is sometimes marketed for birds around 14 weeks and may run slightly lower in protein, around 14–15%. Read the label on whatever bag you buy; manufacturers set their own age and protein guidelines.
When Do Chickens Switch to Grower Feed?
Oregon State Extension recommends starting grower feed at about 6 weeks and continuing until about 17 weeks or just before hens begin egg production. Some producers wait until 7–8 weeks depending on the breed’s growth rate and the specific feed label.
The right moment depends on your birds’ development, not just the calendar. Watch for these signs that chicks are past the starter phase:
- Feathers are filling in and wing feathers are fully developed
- Growth has slowed from the dramatic early weekly gains
- Birds are spending more time foraging and less time at the feeder
The switch to layer feed happens at the opposite end: once the first egg appears, or right around 17–18 weeks for most hybrid layers. That higher-calcium ration is essential for shell strength, and delaying it once laying starts can produce thin-shelled eggs.
The Grower Feed Schedule at a Glance
| Stage | Age Range | Feed Type |
|---|---|---|
| Brooding | Day 1 – 6 weeks | Starter feed (18–20% protein) |
| Growing | 6 – 17 weeks | Grower or developer feed (15–18% protein) |
| Laying | First egg onward | Layer feed (16–18% protein, high calcium) |
This timeline fits standard hybrid layers. Heritage breeds and dual-purpose birds develop slower and may stay on grower feed a week or two longer. The manufacturer’s label on your feed bag is the final authority for that specific product.
Common Grower Feed Mistakes to Avoid
The most frequent error is switching to layer feed too early. That extra calcium serves no purpose in a non-laying bird and can cause kidney strain or urinary problems. Conversely, leaving birds on starter feed past 8 weeks wastes money on a higher-protein ration they no longer need.
Treats are another trap. Scratch grains, kitchen scraps, and mealworms should stay under 10% of total intake. They dilute the balanced nutrition in grower feed, and a bird filling up on corn is not getting the protein and minerals it needs for proper skeletal development.
If you keep a mixed flock with some hens already laying, you have a logistics problem: the layers need calcium, and the growers don’t. Free-choice oyster shell on the side lets laying hens self-supplement calcium while everyone shares the same grower ration, a workable compromise for small backyard flocks.
Grower feed fills a narrow but important window in a chicken’s life. Get the timing right and your pullets will reach laying age with strong frames and healthy organs, ready to produce eggs for years to come.
FAQs
Can chicks eat grower feed instead of starter?
No. Starter feed’s higher protein level (18–20%) supports the fastest growth phase of a chick’s life, and its fine texture suits small beaks. Grower feed at 15–16% protein would shortchange that rapid development. Keep chicks on starter until at least 6 weeks.
Is grower feed the same as layer feed?
No. Grower feed is deliberately low in calcium because growing birds don’t need it yet, while layer feed carries elevated calcium for eggshell formation. Feeding layer feed to immature birds can stress their systems; feeding grower feed to laying hens produces weak shells.
What happens if you feed grower feed to laying hens?
Laying hens need roughly 3.5–4% calcium in their ration to produce strong eggshells. Grower feed typically provides about 1%. Hens on grower feed will produce eggs with thin, fragile shells or stop laying altogether. Switch to layer feed at the first egg.
References & Sources
- Oregon State University Extension. “Feeding Laying Hens (PNW 477).” Provides the grower feed age window, protein percentages, and developer feed guidance used throughout this article.