Feed Conversion Ratio Explained With Worked Examples

Feed conversion ratio is one division: kilos of feed used, divided by kilos of live weight produced. If a batch of broilers ate 2,000 kg of feed and weighed 1,100 kg in total at sale, the FCR is 2,000 ÷ 1,100 = 1.82. Each kilo of chicken took 1.82 kg of feed to make. The lower the figure, the less feed you bought for each kilo you sold.

Feed is the largest cost in any poultry enterprise, commonly around two-thirds of the total, so FCR is the single number that says most about whether a batch made money. It is also widely miscalculated, or calculated once and never used. The examples below follow one batch of 500 broilers through the whole sum, then a layer flock. All cedi prices are examples for showing the method. Put your own in their place.

The formula, and what to count on each side

FCR = total feed used (kg) ÷ total live weight sold (kg)

The division is simple. The care goes into the two figures.

Feed used means every kilo that left the store for that batch: starter, grower and finisher together, including feed that was spilt, eaten by rats, spoilt or carried off. Count bags delivered, subtract what is left at the end, and multiply by the true bag weight. Put a few bags from each delivery on a scale, because a bag sold as 50 kg that weighs 48 kg puts a 4 per cent error into your figure before you start.

Live weight means the total weight of the birds at the farm gate, taken from a scale you trust. If you sell per bird, weigh a proper sample on the day of sale and multiply the average by the number sold. If you sell dressed, weigh a sample alive before slaughter, because dressed weight is only about 70 to 75 per cent of live weight and would make your FCR look far worse than it is.

An FCR has no units and does not depend on batch size, which is what makes it useful. A farmer with 200 birds and one with 20,000 can compare the same number.

Worked example 1: a batch of 500 broilers

Here are the records for an example batch sold at 42 days.

FCR = 2,025 ÷ 1,123 = 1.80

Two other figures fall out of the same records. Feed per bird sold is 2,025 ÷ 478 = 4.24 kg, which is what you use to budget feed for the next batch. Liveability is 478 ÷ 500 = 95.6 per cent.

Strictly, the weight the birds gained is the weight sold minus the weight of the chicks at placement. At about 40 g each, 478 chicks weighed 19 kg, so the gain was 1,104 kg and the FCR on gain is 2,025 ÷ 1,104 = 1.83. The difference is small. Most farms leave the chick weight in. What matters is that you calculate every batch the same way.

Worked example 2: what the dead birds cost

The 22 birds that died ate feed before they died. That feed is in the 2,025 kg, but their weight is not in the 1,123 kg. So the ordinary FCR mixes two things: how well the birds converted feed, and how many you lost.

To separate them, add the weight of the dead birds back in. This is called the mortality-corrected FCR, and it needs one extra record: the approximate weight of each bird you remove. Suppose 9 chicks died in the first week at about 100 g each (1 kg in all) and 13 birds died in weeks five and six at an average of 1.9 kg (25 kg in all).

Corrected FCR = 2,025 ÷ (1,123 + 26) = 2,025 ÷ 1,149 = 1.76

The birds themselves converted feed at 1.76. Mortality moved the batch to 1.80. Notice where the cost came from. The nine early deaths weighed one kilo between them and had eaten almost nothing. The thirteen late deaths had each eaten around 3 kg of feed. A bird that dies in week one costs you a chick. A bird that dies in week six costs you a chick plus most of the feed for a finished broiler, and nothing comes back.

If your ordinary FCR is poor but the corrected figure is good, the problem is late mortality (heat, disease, sudden death in heavy birds) and not feed or feeding. If both are poor, look at feed, wastage and bird health.

Turning FCR into cedis

Feed cost per kilo of live weight = FCR × feed price per kilo

Suppose feed averages GH₵ 400 for a 50 kg bag across the batch, which is GH₵ 8.00 a kilo. At an FCR of 1.80, the feed in every kilo of live chicken costs 1.80 × 8.00 = GH₵ 14.40. At 2.00 it would cost GH₵ 16.00. On the 1,123 kg sold, that difference of GH₵ 1.60 a kilo is GH₵ 1,797.

A handy way to hold this in your head: on this batch, each 0.1 of FCR is about 112 kg of feed, a little over two bags, or roughly GH₵ 900 at the example price. The poultry profit calculator lets you run the whole batch with your own prices.

Comparing a cheaper feed with a dearer one

The same sum settles an argument that comes up every time feed prices rise. Suppose you try two feeds on two batches.

In this example the bag that costs GH₵ 30 more produces chicken for 82 pesewas a kilo less. It could just as easily go the other way, and a dear feed is not automatically a good one. The point is that the price on the bag tells you nothing until you multiply it by the FCR that feed gives on your farm. Compare batches raised in the same season and sold at similar weights, or weather and age will confuse the result.

What a good figure looks like

FCR is not constant through a bird's life. A young chick turns feed into body weight almost kilo for kilo. As it grows, more of each day's feed goes to maintaining a bigger body and less to growth, so the cumulative figure climbs week by week.

The breed figures assume controlled houses, pelleted feed and management by the book. The broiler chicks Halaal Farms Ghana supplies are Ross 308 and Cobb 500, and both breeding companies publish performance targets, so ask which strain your batch is and compare against the right chart. In an open-sided house on mash feed in Ghanaian heat, a batch FCR of roughly 1.7 to 1.9 at 2 to 2.5 kg is a sound result. Above 2.0, something is leaking.

Two rules follow from the table. Compare batches only at similar weights, because a batch sold at 1.8 kg will always show a better FCR than one sold at 2.8 kg, and that says nothing about which was better managed. And remember that each extra week is the most expensive one, a point worked through in our article on when to sell broilers.

Slow-growing birds are a different case. Sasso, Kuroiler, Noiler and cockerels take two to four times as long to reach market weight, so they use far more feed per kilo than a broiler. They are judged on other things: hardiness, the price a coloured live bird fetches, and how much of their feed they find for themselves. Do not hold them to broiler FCR figures.

One step further: the efficiency factor

Because FCR depends on age and weight, integrators use a combined score, the European Production Efficiency Factor, to rank batches of different ages:

EPEF = (liveability % × average weight in kg) ÷ (age in days × FCR) × 100

For the example batch: (95.6 × 2.35) ÷ (42 × 1.80) × 100 = 297. Higher is better. The number means little alone, but tracked from batch to batch on your own farm it rewards the things that matter together: birds alive, weight, speed and feed.

What moves FCR up or down

• Wastage. FCR counts feed that disappeared, not feed that was eaten. Overfilled feeders, rats and spillage in the store all land in the figure. This is usually the quickest gain, and our guide to reducing feed wastage goes through the leaks one by one.
• Feed quality and form. A feed short of energy or of a key amino acid makes birds eat more for the same growth. Pellets and crumbles usually convert better than mash because less is spilt and birds cannot pick out the coarse particles. Mouldy or stale feed converts badly.
• Temperature. Chilled chicks burn feed to keep warm. Heat-stressed birds eat less, so a larger share of what they do eat goes on staying alive and less on growth.
• Gut health. Coccidiosis, worms and bacterial gut infections damage the lining that absorbs nutrients. Feed goes in, and more of it comes out undigested.
• Water. Birds that cannot drink freely do not eat or digest properly.
• The first week. A flock that starts badly stays uneven, and the small birds convert poorly to the end.
• Crowding. Too many birds for the floor, feeder or drinker space means some eat well and others do not.
• Deaths and sale age, as the examples above show.
• Theft and bad records. A bag that left the store by the back gate is in your FCR. A sudden unexplained jump is sometimes a security problem and not a poultry one.

Check FCR during the batch, while you can still act

A figure calculated after the birds are sold can only improve the next batch. You can estimate FCR at any point during a batch with three numbers: feed used so far, birds alive, and the average weight from a sample.

Suppose that on day 28 of a new batch you have 492 birds alive, you have opened 19.5 bags (975 kg), and a sample of 50 birds caught from several parts of the house averages 1.32 kg. Live weight in the house is about 492 × 1.32 = 649 kg, so FCR to date is 975 ÷ 649 = 1.50.

Compare that with your own earlier batches at the same age. If the last three batches were at 1.42 on day 28 and this one is at 1.50, you have two weeks to find the reason while it can still be corrected. How to catch and weigh a fair sample is explained in our article on broiler weight targets.

Layers: feed per dozen and feed per crate

A laying hen is not sold by weight, so the measure changes from feed per kilo of bird to feed per unit of eggs. Internationally this is quoted as kilos of feed per dozen eggs. In Ghana eggs are traded by the crate of 30, so feed per crate is the more practical figure.

Feed per crate = feed used in the period (kg) ÷ crates collected in the same period

Take an example week for 1,000 hens.

At an example layer feed price of GH₵ 7.50 a kilo, the feed in each crate costs 4.16 × 7.50 = GH₵ 31.20. That is the figure to hold against your crate price each week. It covers feed only, not labour, medication or the cost of rearing the pullet.

Now let the same hens fall to 70 per cent lay while eating the same feed. Eggs drop to 4,900, or 163.3 crates. Feed per crate rises to 805 ÷ 163.3 = 4.93 kg, and the feed cost of a crate to GH₵ 36.97. Nothing changed in the feed store. The hens still ate 805 kg. The whole extra cost came from eggs that were not laid, which is why laying percentage is the first thing to protect. Our article on raising your laying percentage covers how.

As a rough guide, a well-managed brown layer flock near peak uses about 1.5 to 1.7 kg of feed per dozen, or 3.8 to 4.3 kg per crate. The figure rises as the flock ages and lay declines. It is pushed up by feed wastage, by hens that eat but do not lay, by overweight birds and by cold nights, and it can look deceptively good in hot weather when hens eat less but also lay smaller eggs.

Egg size is the reason nutritionists use a third version, kilos of feed per kilo of eggs. In the example week, at an average egg weight of 60 g, the flock produced 349 kg of eggs, so the ratio is 805 ÷ 349 = 2.3. Use it if you sell graded eggs by size.

Recording habits that make the number trustworthy

1. Write down every bag as it leaves the store, with the date and the pen it went to.
2. Weigh at least three bags from every delivery.
3. Count the feed left in the store and in the feeders on the day the batch ends.
4. Record each dead or culled bird on the day, with an estimate of its weight.
5. Keep the buyer's weighing slip, or your own sample weights, for every sale.
6. For layers, total the week's feed and eggs on the same day each week.

None of this needs more than a notebook. Layouts for the daily and batch sheets are in our article on poultry records every farmer should keep.

A good FCR starts with a strong, even chick and a well-prepared brooder, and it is easiest to measure when you know exactly how many birds you placed. Halaal Farms Ghana supplies broiler and layer chicks in boxes of 50 and confirms price, hatch date and delivery cost before you pay. If you want help reading the figures from your last batch before you plan the next one, call 024 915 1503 or send the order form. Advice is free before and after an order.

Questions farmers ask

Written by the Halaal Farms Ghana team. We hatch and import day-old chicks at Opeikuma, Kasoa, and deliver to all 16 regions. This article is general guidance for farmers. For diagnosis and treatment of sick birds, speak to a vet or your district veterinary office.

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