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Broiler production efficiency index (IEP)

See the efficiency of the broiler batch from livability, weight, age and feed conversion.

Pre-sizing and estimating tool: the results do not replace a design, calculation, or report signed by a qualified professional, nor verification against the applicable standards.

Preliminary estimateRevision 12/11/2026
Batch results

Use the data from the closed batch: actual viability, weighed average weight and cycle conversion. The default values are examples only.

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—Production efficiency index (IEP)
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IEP by feed conversion

IEP with conversions of 1.6 to 2,0, keeping livability, weight, and age; the highlighted bar is yours.

Tap the chart to see the values.

IEP by livability

How viability from 90% to 98% changes the IEP, with the other data fixed; the point is your flock.

Tap the chart to see the values.

What if the data changes?

Drag the controls to simulate data different from what you entered (from 30% less to 30% more) and watch the result change instantly.

Tap the chart to see the values.

IEP by livability and conversion

IEP of the batch for livabilities of 90% to 98% and conversions of 1.6 to 1,9, with the weight and age entered.

Step by step with your numbers

The calculation done in steps, with the values you entered.

    The calculation memo gathers this page's inputs, results, equations, assumptions, and references, with fields for project, responsible person, and review. The full report also includes the charts and interpretations, in color. In the print window, choose Save as PDF.

    How to use

    Enter the batch's livability, the average weight at slaughter, the age in days, and the feed conversion. The calculator shows the IEP and how it changes with conversion and livability.

    Worked example

    Livability of 96%, average weight of 2.5 kg, 42 days and feed conversion of 1.70.

    IEP = (96 × 2.5) ÷ (42 × 1.70) × 100 = 240 ÷ 71.4 × 100 = 336.

    Precautions

    • Average weight and conversion from a single weighing at the end of the batch may not represent the whole cycle.
    • For the intake and conversion of each stage, see the feed intake and feed conversion.
    • For the stocking weight in the shed, see the housing density.

    Method, assumptions, and references

    Equations used

    IEP = (Livability (%) × Average weight (kg)) ÷ (Age (days) × Feed conversion) × 100

    Assumptions and limits

    • Livability = birds processed ÷ birds placed, in percent.
    • Average weight and feed conversion of the whole batch, at slaughter.
    • Formula used in comparisons between batches of the same genetic line and system; it is not an absolute measure of performance.

    Standards and technical documents

    • European production efficiency factor (EPEF), used in technical reports for broiler chickens (current edition).

    Frequently asked questions

    What is a good IEP?

    There is no single number. It is used to compare batches of the same line, system, and region. Compare with your farm's history.

    Why does viability matter so much?

    Because each bird lost is a housing and feed cost with no product sold. One point less of viability lowers the IEP almost as much as an increase in feed conversion.

    Can I use the IEP to compare strains?

    Yes, as long as management conditions are similar. Differences in climate, health and density change the result.

    What is the difference for feed conversion?

    Feed conversion only shows feed efficiency. The IEP combines viability, weight and age into one performance measure for the flock.