Slaughter yield and carcass analysis in broilers
Slaughter yield is the percentage of meat left from a bird after slaughter — the higher it is, the more meat from one broiler. We explain how to calculate it, what raises or lowers the result, and how carcass assessment works at the slaughterhouse: breast, legs, fat and defects that lower the grade.
verifiedFrom the team that has organised work on poultry farms for years.
When a broiler reaches the slaughterhouse, the farmer and the processing company look at two things: how many birds arrived alive and what the slaughter yield is. Good yield means more meat from the same number of animals and a lower cost per kilogram of product. It is the result of the whole cycle — genetics, nutrition, health and proper preparation for slaughter.
How is slaughter yield calculated?
The formula is straightforward: slaughter yield (%) = (carcass weight ÷ live weight before slaughter) × 100%. The result depends on exactly what counts as the carcass: with or without the neck and giblets, and after water-chilling (absorbed water slightly increases weight) or air-chilling. For a commercial broiler, the dressing percentage of an eviscerated carcass with neck is indicatively 70–75%. Always ask your slaughterhouse how it calculates its figure so you are comparing like with like.
Where do the numbers in this guide come from?
The percentage values given are indicative and are based on data published by genetic line producers (Aviagen, Cobb-Vantress) and slaughterhouse practice. They may differ depending on broiler line, nutrition, slaughter weight and chilling method. Treat them as reference points, not fixed standards.
Slaughter yield — what it is and how to measure it
Three things every farmer should understand before comparing their result with a neighbour's.
Ratio of carcass weight to live weight
Slaughter yield is simply: take the weight of the finished carcass and divide it by the live weight of the bird just before slaughter, then multiply by 100%. If a bird weighed 2.5 kg live and the eviscerated carcass weighs 1.8 kg, the yield is 72%. The higher the percentage, the more meat you get from one bird.
Eviscerated carcass with neck or without?
This is a trap when comparing results: different slaughterhouses calculate differently. An eviscerated carcass with neck gives a higher figure than one without neck and giblets. A carcass after water-chilling (immersion chilling) weighs slightly more than after air-chilling because it absorbs water. Always check exactly what your slaughterhouse counts before saying you have "70%" or "75%".
EWW/EPEF index — one number for the whole flock
The European Production Efficiency Factor (EPEF, Polish abbreviation EWW) combines slaughter weight, age, flock survival rate and feed consumption into a single number. It is a tool for comparing flocks with each other and with other farms — one flock may have high slaughter yield but poor feed conversion; EPEF shows the overall result. Details in the guide on the EWW/EPEF index for broilers.
What affects broiler slaughter yield
Yield is the combined result of genetics, nutrition and what happens in the few hours before slaughter. Below are the key factors.
Genetics — meat lines have large breasts
Commercial broiler meat lines (Ross, Cobb, Hubbard) are bred specifically for high slaughter yield and a large breast muscle share. This is the single strongest factor — good genetics gives several percentage points more than an average line. Slaughter weight also matters: a heavier bird generally has a slightly higher breast share than a very light one.
Nutrition — protein and energy in the right ratio
Feed rich in protein and energy promotes muscle building (including the breast muscle) rather than fat deposition. Too much fat in the carcass is a loss — for both the farmer and the meat buyer. Balanced nutrition throughout the cycle is one of the few factors the farmer can directly influence. More in the guides on broiler weight and growth — table and FCR — how to calculate feed conversion.
Proper feed withdrawal before slaughter — empty crop and intestines
The bird should reach the slaughterhouse with an empty digestive tract — an empty crop and intestines mean a clean slaughter and the correct live weight. Too short a withdrawal: risk of contaminating the carcass with gut content and an artificially lower yield figure (gut content has weight). Too long a withdrawal: the bird loses muscle mass, yield drops and stress rises. The optimal withdrawal period is indicatively 8–12 hours including transport. Details in the guide on feed withdrawal before broiler slaughter.
Transport and stress — bruising and fractures lower the grade
Stress, overcrowding during catching and transport, excessively high or low temperature — all of these cause bruising, wing and leg fractures, and in extreme cases mortality before reaching the slaughterhouse. Every bruise and fracture is a carcass defect that lowers grade and price. Proper live bird collection is described in the guide on broiler live bird collection.
Flock health — disease lesions visible at the slaughterhouse
Respiratory disease, joint problems, liver lesions — all of these only become apparent during post-mortem inspection at the slaughterhouse. A flock that was sick will have lower yield and more carcasses condemned or downgraded. Health management throughout the cycle translates directly into slaughterhouse results.
Age and slaughter weight — when to slaughter?
Every broiler line has an optimal slaughter age and weight at which the ratio of meat to fat and feed consumption is best. Too early: lower carcass weight but usually a clean carcass with few defects. Too late: higher feed costs, more fat, higher risk of leg and heart problems in heavy birds. More in the guide on broiler weight and growth.
What is assessed on the carcass after slaughter
The slaughterhouse and the buyer look at the same carcass, but each part has its own value — and its own defects that lower the grade.
Breast meat — the most valuable part
The breast is the most expensive and most sought-after part of the broiler. Good meat lines have a breast muscle share of indicatively 20–25% of carcass weight. A large, symmetrical breast with no surface defects is a sign of good genetics and good nutrition. Asymmetry, bruising on the breast, or haemorrhages under the skin are defects that lower the grade and the price per kilogram.
Legs — thigh and drumstick
Legs (thigh and drumstick) are the second most valuable part after the breast. The buyer assesses weight, muscle cross-section and the absence of defects. Footpad dermatitis (FPD) is particularly visible on the legs — skin lesions on the underside of the foot caused by wet litter. FPD is graded by the slaughterhouse on a point scale; a result above a certain threshold lowers the grade of the whole leg batch and is an important warning signal to the farmer about litter condition.
Fat and wings
Excessive fat deposits (particularly in the abdominal cavity and under the skin) are a loss — the buyer pays for meat, not fat. Fat also means higher feed cost with no return. Wings are assessed for fractures and bruising — a broken or bruised wing is the result of poor catching or transport and directly reduces carcass value.
Carcass defects that lower grade and price
A few problems that recur most often and have a direct impact on settlement with the slaughterhouse.
Bruising and haemorrhages
Bruising on the breast, wings and legs is the most common broiler carcass defect. It results from poor catching (too tight a grip, too many birds in one crate), transport (jolts, birds falling) or a failed stun. The more bruised areas, the lower the grade and the lower the price.
Wing and leg fractures
Fractures are a direct economic loss — the damaged part is valued much lower or cut off as waste. The most common causes are overly rough catching, too high a density in the transport crate, and jolting during loading and unloading.
Footpad dermatitis (FPD)
Footpad dermatitis (FPD) consists of skin lesions on the underside of the foot, ranging from slight redness to deep ulceration. The cause is wet, contaminated litter. The slaughterhouse scores FPD on a point system — a result above a set threshold lowers the grade of the whole leg batch. It is a signal that something is wrong with the litter or the drinkers in the house.
Carcasses condemned for health reasons
Carcasses with visible disease lesions (liver, lung, yolk-sac changes, joint inflammation) are condemned or partially trimmed by the slaughterhouse vet. Every condemned carcass is a total loss. High condemnation rates signal a health problem in the flock — to be investigated with the vet.
Frequently asked questions about slaughter yield
What is broiler slaughter yield?add
Slaughter yield is the ratio of finished carcass weight to live bird weight before slaughter, expressed as a percentage. Formula: (carcass weight ÷ live weight) × 100%. For a commercial broiler it is indicatively 70–75%, depending on how the slaughterhouse defines the carcass (with or without neck, after water or air chilling). A higher figure means more meat from one bird.
What affects broiler slaughter yield?add
The main factors are: genetics (meat lines have higher yield), nutrition (the right protein and energy level), proper feed withdrawal before slaughter (empty crop and intestines mean a clean carcass and correct weight), stress and transport (bruising and fractures lower the grade), and flock health (disease lesions show up at the slaughterhouse).
How is slaughter yield calculated?add
The formula is: (carcass weight ÷ live weight before slaughter) × 100%. It is important to know what your slaughterhouse counts as "carcass weight" — whether it is the eviscerated carcass with neck, without neck, after water chilling or air chilling. Different definitions give different figures that cannot be directly compared.
What is FPD — footpad dermatitis?add
Footpad dermatitis (FPD) consists of skin lesions on the underside of the broiler's foot — from slight redness to a deep ulcer. The cause is wet and contaminated litter. The slaughterhouse scores FPD on a point scale and above a certain threshold it lowers the grade of the leg batch. Severe FPD signals a problem with litter management or the drinkers in the house.
What is the EWW/EPEF index?add
The European Production Efficiency Factor (EPEF, Polish abbreviation EWW) is a single number that combines slaughter weight, slaughter age, flock survival rate and feed consumption. It allows flocks to be compared with each other and with other farms. High slaughter yield with poor FCR can result in a low EPEF — which is why it is worth looking at both indicators. Details in the guide on the EWW/EPEF index for broilers.
How do bruising and fractures affect settlement with the slaughterhouse?add
Every bruise and fracture is a carcass defect that lowers its grade and price per kilogram. Carcasses with major bruising or broken wings may be graded lower or the damaged part cut off as waste. The most common causes are rough catching, too high a density in the transport crate, and jolting during loading and unloading.
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