Feed Conversion Ratio: What Buyers Should Specify, Measure and Verify

Short answer: FCR is feed consumed divided by weight gained. It is the bridge between a feed price and a farm result, so it belongs in every commercial comparison — but it cannot be guaranteed by a supplier, because most of the variables sit on the farm. Specify what the supplier controls (composition, digestibility indicators, physical quality) and evaluate offers on cost per kilogram of gain using your own measured FCR.

Why price per tonne misleads

Two offers, USD 470 and USD 495 per tonne. The cheaper one looks like an easy decision until the arithmetic is done on the animal instead of the invoice. If the more expensive feed reduces the feed needed per kilogram of gain by even a small margin, its cost per kilogram of live weight can be lower — and cost per kilogram of gain, not price per tonne, is what the business actually pays.

The reverse is equally true. A premium formula that does not change the farm result is simply a more expensive input. Neither claim can be settled by argument; both are settled by measurement.

How to measure FCR so the number means something

1. Fix the boundaries. Same population, same period, same weighing method. Feed delivered is not feed consumed — account for bin residue, spillage and any feed left at the end of the cycle.
2. Correct for mortality. Removing dead animals from the gain figure without removing the feed they ate inflates FCR; a standard mortality-corrected calculation avoids arguing about it later.
3. Correct for weight. FCR rises with slaughter weight in most species, so compare batches at the same target weight or use an adjusted FCR.
4. Record the conditions. Season, ambient temperature, stocking density, health events, water quality, and any ration change mid-cycle. Without those, two cycles are not comparable.
5. Use enough cycles. A single batch is an anecdote. A rolling average across several cycles, on the same house or pond, is evidence.

What the feed actually controls

The supplier controls the input, not the outcome. The controllable, specifiable levers are:

• Energy and amino acid balance relative to the species and stage — the primary driver of efficiency the formula can influence.
• Digestibility. Raw material quality, heat treatment, particle size and enzyme use change how much of the declared nutrient is available.
• Physical quality. Fines are eaten less efficiently or not at all; poor water stability in aquafeed puts nutrition into the water column. Both show up as worse FCR without any change in composition.
• Consistency between batches. Variability forces the animal to adapt repeatedly and blurs any measurement you attempt.
• Freshness and oxidation. Rancid fat depresses intake and performance, which is why shelf-life and peroxide limits belong in the specification.

Everything else — genetics, brooding, ventilation, water, health programme, feeder space, management — sits on the farm. This is why an FCR warranty from a feed supplier is a commercial red flag rather than a benefit: it is a promise about someone else's operation.

Using FCR in a tender without over-promising

A workable structure for a serious feed tender:

Ask every bidder for the same evidence pack, and score it the same way. Where a supplier cites trial results, ask for the conditions: species, genetics, number of animals, control diet, duration, and who ran it. A result without conditions is marketing.

A worked comparison frame

Baseline: your own recorded FCR on the current feed, averaged over the last six cycles, at a defined target weight. For each offer: indicative cost per kg gain = feed price per kg × assumed FCR. Sensitivity: repeat with FCR at baseline, baseline −0.05 and baseline +0.05. Decision rule: if an offer only wins under an FCR improvement the supplier cannot evidence, treat it as the more expensive offer.

That frame is deliberately conservative. It rewards suppliers who can substantiate a specification and neutralises claims that cannot be tested.

Where this fits in procurement

FCR is the reason the composition specification and pellet quality clauses matter commercially rather than technically. It is also the practical reason many operations eventually evaluate their own production: run the numbers on the feed requirements calculator and the calculators hub before assuming either buying or producing is cheaper.

A worked quotation excerpt

Anonymised and illustrative, reconstructed from the structure of offers buyers receive rather than attributed to any named supplier — this is how a performance-relevant quotation is framed:

Product quoted: Broiler finisher pellet, per buyer specification. Price: USD 424 / t CFR, validity 30 days. Nutrient density: ME 3,150 kcal/kg; dig. lysine 1.02%. Supplier note: Our finisher runs approximately 60 kcal/kg above the reference formula; no performance guarantee is offered, as feed conversion depends on genetics, health status and farm management outside our control.

That last line is the honest one, and you should expect it. No serious supplier guarantees FCR. What the quotation gives you is nutrient density and price; you convert those into cost per kilogram of liveweight yourself using your own historical conversion, which is exactly the calculation shown above.

Related in this cluster: how to write a feed specification, feed conversion ratio, pellet quality and PDI, extrusion vs pelleting, raw material specifications, sampling and laboratory testing, mycotoxins and feed safety limits, premix and additive specification.

Next step. Turn the numbers into a quotable document: size the volume with the feed requirements calculator, check the commercial frame on the calculators hub, then submit the specification through the RFQ intake. A reviewer reads every brief before suppliers see it.

*FeedMatch Group is an independent, human-led animal feed sourcing and RFQ platform. We are not a feed producer, equipment manufacturer, EPC contractor, farm, laboratory, nutritionist, lender or financial advisor. Every requirement is reviewed by a person before any supplier is approached, and nutritional or veterinary decisions remain with your own nutritionist or veterinarian.*