Broiler nutrition — standards (protein, energy, phases)
Broilers grow very fast — they build muscle in just a few weeks. For this to happen, the feed must match the bird's needs at every growth stage: high protein at the start, then progressively more energy. We explain how multi-phase feeding works, what a complete compound feed is and why grain alone is not enough, and which amino acids (the building blocks of protein: lysine, methionine) matter most.
verifiedFrom the team that has organised work on poultry farms for years.
A broiler (meat chicken) reaches slaughter weight in 35–42 days. Such rapid growth is only possible when the feed precisely matches the bird's needs at each stage. Too little protein early on — muscle growth slows. Too little energy at the end — the bird doesn't reach full weight. This guide is part of the broiler cluster — you can find the full picture in the guide on broiler farming.
Where do the numbers in this guide come from?
The protein and energy ranges given here are INDICATIVE — based on IZ-PIB "Normy żywienia drobiu" (2025) and Aviagen Ross 308 Nutrition Specifications (2022). The exact values depend on the genetic line, chick supplier, rearing programme and farm conditions. Always consult your feed supplier or animal nutritionist. The guide to calculating feed use and efficiency is at broiler FCR — how to calculate it.
Multi-phase broiler feeding — how the feed changes every few weeks
Broiler feeding typically uses 3–4 feeds with different compositions. High protein at the start, then progressively more energy. Indicative values from IZ-PIB and Aviagen Ross 308*.
Starter feed (approx. days 0–10)
Chicks need a great deal of protein because they are building muscle intensively. Protein in starter feed is indicatively about 22–23% (crude protein). Energy — about 12.5 MJ/kg. The feed takes the form of crumble (crushed pellets) — easier for a small chick to consume before it can handle hard pellets. Amino acids (the building blocks of protein: lysine, methionine) must be well balanced from day one. More on getting started: broiler farming.
Grower feed (approx. to day 24–28)
The bird is growing intensively but is already larger and stronger. Protein drops indicatively to about 21%. Energy rises to about 12.9–13.1 MJ/kg. Feed form changes from crumble to full pellet — the bird can now swallow it without difficulty. Compound feeds suited to this phase are covered in the guide compound feeds for poultry.
Finisher feed (from approx. day 24–28 to slaughter)
The broiler is completing growth, depositing muscle tissue and some fat. Protein drops indicatively to about 19–20%. Energy is at its highest in the whole programme — about 13.2–13.4 MJ/kg. Pelleted complete compound feed. Finisher feed must comply with withdrawal-period requirements (the time between the last administration of a preparation and slaughter) — always check with your feed supplier and veterinarian.
Pre-starter and second finisher — optional
Some rearing programmes include a pre-starter feed in the first 3–5 days — very high digestibility and protein content. There may also be a second finisher with even lower protein, given in the final days before slaughter. This depends on the breeding programme and the requirements of the slaughterhouse buyer. Ask your feed consultant.
What broilers need beyond protein and energy — calcium, water and feed form
Protein and energy alone are not enough. These four rules determine flock health, growth and feeding efficiency.
Complete compound feed — grain alone is not enough
Complete compound feed (a ready-made, complete mixture) provides protein, energy, minerals (calcium, phosphorus), vitamins and amino acids in proportions matched to the growth stage. Grain alone (wheat, maize) provides energy but lacks sufficient protein, amino acids, calcium and vitamins. Feeding grain alone is a straightforward way to achieve poor results and health problems in the flock. More on feed mixtures: compound feeds for poultry.
Calcium and phosphorus — for strong bones
Broilers grow fast and bones must keep pace with muscles. Calcium is indicatively about 0.9–1.0% in the feed; available phosphorus (the fraction of phosphorus the bird can actually use from food) should follow feed supplier recommendations, as it depends on the phase and phosphorus source. Calcium deficiency or poor ratios weaken the skeleton and can cause leg problems.
Ad libitum feeding — feed and water available at all times
Broilers should have access to feed and clean water around the clock (ad libitum feeding). Even a few hours without feed slows growth. Water is equally important — a bird drinks about 1.8–2 times more water than it eats feed (by weight). Check and clean drinkers every day, especially in summer. Calculating feeding efficiency: broiler FCR — how to calculate it.
Feed form matched to age — crumble, then pellet
A small chick cannot swallow a hard pellet — that is why crumble (crushed pellets, easy to pick up) is used at first. Once the bird is larger (typically after about day 10), it moves to full pellets. Feed form affects intake and feeding efficiency. Too coarse a pellet too early means lower intake and slower growth. Feed recipe composition: feed recipe calculator.
Frequently asked questions about broiler nutrition
How much protein does a broiler need in starter feed?add
Indicatively about 22–23% crude protein in starter feed (days 0–10), according to IZ-PIB "Normy żywienia drobiu" 2025 and Aviagen Ross 308 Nutrition Specifications 2022. The exact value depends on the genetic line and rearing programme. Always consult your feed supplier or animal nutritionist.
Why does protein in broiler feed decrease with age?add
A young bird builds muscle intensively and needs many amino acids (the building blocks of protein: lysine, methionine). An older broiler grows more slowly and needs more energy to finish growing and deposit fat. That is why starter feed contains about 22–23% protein while finisher feed contains only about 19–20% — but with higher energy content.
What are amino acids and why are lysine and methionine important for broilers?add
Amino acids (the building blocks of protein: lysine, methionine) are the components from which the bird's muscles are built. Lysine and methionine are most important because they determine how efficiently the bird can build muscle tissue. If they are lacking in the feed, the bird does not grow properly — even if the overall protein content appears sufficient. A good complete compound feed has amino acids balanced to the energy level.
Can broilers be fed grain alone (wheat, maize)?add
No — grain alone is not sufficient. Wheat and maize provide energy but have too little protein, amino acids, calcium and vitamins. A bird fed only grain grows slowly, has weak bones and is more susceptible to disease. Broilers need complete compound feed (a ready-made, complete mixture) with a vitamin-mineral premix and the appropriate amino acid profile.
What is the difference between crumble and pellet?add
A pellet is feed compressed into hard cylinders. Crumble (crushed pellets) is a pellet broken into smaller pieces that are easier for a small chick to pick up. At the start of rearing (indicatively up to about day 10) birds receive crumble, then the switch is made to full pellets. Introducing coarse pellets too early reduces feed intake and slows growth.
How often should the type of feed be changed (transitions between phases)?add
In a typical 3-phase rearing programme there is a starter feed (indicatively days 0–10), a grower feed (to about day 24–28) and a finisher feed (to slaughter). Transitions are usually made gradually — over 2–3 days old and new feed are mixed in increasing proportions of the new until the switch is complete. Monitor feed intake during the transition. The full cycle is covered in broiler feeding phases — table.
How important is water in broiler nutrition?add
Very important. A bird drinks indicatively about 1.8–2 times more water than it eats feed (by weight). Even a few hours without clean water limits feed intake and slows growth. Water temperature matters in summer — birds drink more readily when water is neither too cold nor too warm. Check and clean drinkers every day.
Sources & resources
Manage broiler nutrition in DlaFerm.pl
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