Broiler Feed Conversion Ratio (FCR) Calculator
Broiler flock FCR from feed and live weight (average bird or total scale weight, kg or lb), FCR adjusted to a standard weight, mortality-corrected FCR, FCR on gain, average daily gain, livability, EPEF and European Broiler Index, a comparison with the Ross 308 performance objective at your age and weight, feed and production cost per bird and per kg, margin over costs, stocking density and what each 0.05 of FCR is worth.
How it works
FCR = feed eaten (delivered − left over) ÷ live weight sold; adjusted FCR = FCR − (weight − standard weight) × FCR change per kg (0.03 per 100 g = 0.3 per kg by default); mortality-corrected FCR = feed ÷ (live weight sold + dead birds × their average weight); FCR on gain = feed ÷ (live weight − chick weight); ADG = (final − chick weight) ÷ days; livability = sold ÷ placed; EPEF = livability % × live weight (kg) ÷ (age × FCR) × 100; EBI = livability % × ADG (g) ÷ (FCR × 10); feed cost per kg live = FCR × feed price
Feed conversion ratio — kilograms of feed per kilogram of live bird — is the number that decides broiler profitability, because feed is roughly two-thirds of the cost of production. Enter the live weight as an average bird or as the total from the scale tickets, in kilograms or pounds, and subtract any feed left in the bins so only feed actually eaten counts. Because FCR worsens as birds get heavier and older, comparisons between flocks are adjusted to a common weight: the traditional rule is about 0.03 per 100 g, while the Ross 308 2022 objectives rise closer to 0.02 per 100 g, so both the standard weight and the slope can be changed. Birds that died ate feed but were never sold; adding their average weight gives a mortality-corrected FCR that separates feed efficiency from mortality. The European Production Efficiency Factor and the European Broiler Index bundle FCR, growth rate and livability into one score so flocks of different ages and weights can be ranked — 350–400 is typical for good commercial flocks and over 400 is excellent. The comparison with the Ross 308 objective shows how far the flock is from the breed’s potential at the same age and at the same weight. With a live price and the other costs per chick, the calculator also gives the margin, the break-even live price and the break-even FCR, and the table shows what each 0.05 of FCR is worth in feed. Wasted feed, poor water quality, heat stress, coccidiosis and late mortality are the usual reasons FCR drifts up.
Worked example
10,000 chicks placed, 9,620 sold at 2.6 kg on day 40 after eating 40,000 kg: 25,012 kg live, FCR 1.599 (≈ 1.569 adjusted to 2.5 kg), ADG 64 g/day, livability 96.2%, EPEF 391 — good — and EBI 385. At 48¢/kg feed, feed alone is 77¢ per kg live weight and feed plus chick about $2.57 per bird. The Ross 308 objective at 40 days is 2.80 kg at FCR 1.493; matched on weight, Ross reaches 2.6 kg at about 38 days with FCR 1.457, so this flock is 0.143 behind. Cutting FCR by 0.05 would save about 1,250 kg of feed, or $600 on this flock.
Sources: Aviagen — Ross 308 Broiler Performance Objectives 2022 · Aviagen — Optimizing Broiler Feed Conversion Ratio (Ross Tech Note) · Council Directive 2007/43/EC — protection of chickens kept for meat production
Frequently asked questions
Should feed left in the bins be counted?
No — count only feed actually consumed: delivered minus what remains at harvest, minus any spilled or removed. Enter the leftover under More options and the calculator subtracts it.
Why does mortality distort FCR?
Dead birds ate feed but contribute no sold weight, so late mortality raises FCR sharply; that is why EPEF weights livability alongside conversion. Enter the average weight of the birds that died to see a mortality-corrected FCR that isolates feed efficiency.
What is a good FCR for broilers?
For a modern fast-growing strain, the Ross 308 2022 objective is about 1.40 at 35 days (2.3 kg), 1.49 at 40 days (2.8 kg) and 1.53 at 42 days (3.0 kg). Commercial flocks usually run 0.05–0.15 above the objective; slower-growing and free-range birds 2.0–2.8.
Why adjust FCR to a standard weight?
Heavier birds eat more per kg of gain, so a flock grown to 3 kg will always look worse than one sold at 2.2 kg. Adjusting both to the same weight — 2.5 kg here, or whatever your integrator uses — makes the comparison fair. The slope is an assumption: 0.03 per 100 g is the old rule, the current Ross curve suggests about 0.02.
What is the difference between EPEF and EBI?
Both combine livability, growth and FCR. EPEF uses final weight ÷ age; the European Broiler Index uses average daily gain, which excludes the chick weight. They give similar numbers and are read on the same scale (above 400 is excellent).
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Farm planning estimate. Breeds, climate, feed quality and local extension guidance change the numbers — use this to plan, and your own records to manage.