Starter-grower-finisher feed phases

Phase-feeding is the practice of supplying broiler chickens (and analogously, layer pullets) with a sequence of nutritionally distinct rations matched to the bird's changing nutrient requirements through the production cycle. The standard broiler programme uses three phases — starter, grower and finisher — while the layer-pullet programme runs starter-grower-developer-prelay-layer phases.

Principle

Young chicks need a high concentration of crude protein and essential amino acids per unit of feed to support rapid muscle, feather and skeletal development; older birds need a higher proportion of energy to support finishing weight gain. Feeding the youngest, most demanding ration to the whole flock would overspend on protein for older birds and increase nitrogen excretion; feeding a uniform low-protein ration would limit early growth and worsen feed conversion ratio (Feed Conversion Ratio). Phase-feeding aligns ration nutrient density to bird age, reducing feed cost per kilogram of live weight and lowering nitrogen excreted in litter.

Broiler phase targets

Starter — weeks 0-3, 22-24% crude protein, high amino-acid density, high energy. Typically supplied as crumbles to encourage early intake at brooding (Brooding Chicks).
Grower — weeks 3-6, 20-22% crude protein, slightly lower lysine and methionine, balanced energy.
Finisher — week 6 to market age, 18-20% crude protein with higher energy density and reduced amino acids to drive finishing weight gain.

Each phase change is typically made over a few days by gradual blending of the next phase into the current one to avoid disrupting intake. Phase rations are supplied either as branded compound feed or as on-farm self-mixed feed (Self Mixed Poultry Feed).

Layer phase targets

Replacement pullets follow a starter-grower-developer sequence (with protein stepping down and calcium held low), then a prelay diet (week 16-18) raising calcium to support medullary-bone reserves, then a layer diet from point-of-lay (week 18-19) with calcium at 3.5-4.5% to support shell formation. Commercial layer farms (Commercial Layer Farming) running BV-380 (Layer Chicken Bv 380) and similar strains follow this sequence through to spent-hen sale.

Adoption context

Phase-feeding is universal in commercial integrated broiler operations (Contract Broiler Farming). Indian feed manufacturers — Godrej Agrovet, CP, Venky's and others — sell phase-specific products in both pellet and crumb form. Standalone broiler farms and country-chicken units that self-mix often run a two-phase (starter, finisher) simplification to reduce ingredient handling.

Limitations

Phase transitions, if mistimed, depress intake and raise mortality (Poultry Mortality Management). Phase-feeding does not compensate for ingredient-quality failure: mouldy maize or under-dosed methionine will undermine performance regardless of the formulation calendar.

References

Broiler Feed Breakdown — Feeding for Fast, Healthy and Ethical Growth. Kreamer Feed.