Broiler stocking density — kg/m² and birds/m²
Broiler stocking density is measured in kilograms of live weight per square metre because the birds grow — the number of chicks placed at the start is not enough on its own. We explain in plain language what kg/m² limits apply in the EU, how to convert them to birds and what happens when density is too high.
verifiedFrom the team that has organised work on poultry farms for years.
Stocking density is one of the most important parameters in broiler production. Too high a density means wet litter, worse footpad condition (footpad dermatitis — lesions on the underside of the feet), slower growth and more mortality. Too low a density means higher costs per square metre of house. The broader picture of broiler production is in the guide on broiler farming.
Why do we measure in kilograms, not in birds?
A day-old chick weighs about 40–45 g; a broiler at slaughter weighs 2–3 kg or more. If we kept the number of birds per m² constant, the actual density (in kg/m²) would rise on its own as the birds grew and could exceed the legal limit mid-cycle. That is why the law sets the threshold in kilograms of live weight per square metre — that is the combined live weight of all birds at any given moment divided by the floor area of the house.
Where do the numbers in this guide come from?
The density limits come from Council Directive 2007/43/EC on the protection of chickens kept for meat production. Example slaughter weights and the conversion to birds per m² are indicative and depend on the genetic line, feed and farm conditions. Ross 308 and similar lines according to Aviagen guides — treat the numbers as a reference, not a fixed norm. Welfare programme details and footpad condition are covered in separate guides: poultry welfare — subsidies and footpad dermatitis — broiler footpad quality. Bear in mind that the 33/39/42 kg/m² limits are the legal limits. The science goes further — in its 2023 opinion EFSA recommends a much lower density (around ≤11 kg/m²) and slower growth — but these are scientific recommendations, not binding standards; the law (Directive 2007/43/EC) still permits 33–39 kg/m².
How to calculate broiler stocking density — from kg/m² to birds/m²
- 1
Choose the correct kg/m² limit
Three density levels apply under EU Directive 2007/43/EC. The basic level is 33 kg/m² — available to any producer without additional conditions. The 39 kg/m² level can be used after meeting additional requirements: maintaining welfare documentation, achieving good indicator results (mortality rate, footpad score) and passing an inspection. The maximum level of 42 kg/m² is possible with very good welfare indicators and approval by the competent authority (local veterinary officer). Before planning stocking, check which level applies to your farm for the current cycle.
- 2
Calculate how many birds fit per m²
The formula is simple: birds per m² = limit (kg/m²) ÷ planned slaughter weight (kg). Example A: 39 kg/m² ÷ 2.6 kg slaughter weight = about 15 birds per m². Example B: 33 kg/m² ÷ 2.5 kg slaughter weight = about 13 birds per m². In practice you use the planned slaughter weight, not the chick placement weight — because the limit applies throughout the cycle, right up to slaughter. If you plan thinning (removing part of the flock before the main slaughter), account for the fact that density will be highest just before the thin and lowest just after.
- 3
Calculate the total number of chicks for the whole house
Once you know how many birds fit per m², multiply by the usable floor area of the house (in m²). Example: 1,000 m² house, 39 kg/m² limit, planned slaughter weight 2.6 kg → 15 birds/m² × 1,000 m² = 15,000 birds. Remember that only the usable floor area accessible to the birds counts — not partitions, closed feeder channels, etc. Build in a small safety margin (e.g. deduct a few percent) because mortality reduces density throughout the cycle.
- 4
Check that you meet the welfare conditions
If you want to keep stocking above 33 kg/m², you must maintain welfare documentation and monitor your indicators over consecutive cycles. Key indicators are: the daily mortality rate, total cycle mortality, and footpad dermatitis scores at slaughter. If results deteriorate, you may be required to reduce stocking in the next cycle. Full requirements and welfare subsidy details are in the guide on poultry welfare — subsidies.
- 5
Factor in welfare programmes and contract requirements
Many welfare programmes (e.g. agri-environmental subsidies) or buyer contract requirements specify a density lower than the legal maximum. A typical requirement is around 30 kg/m² — about 15% below the basic 33 kg/m² threshold. At a slaughter weight of 2.5 kg that gives about 12 birds/m². Before each cycle, check the terms of your contract or programme — you may legally be allowed more, but your agreement may say less. More on subsidies in the guide on poultry welfare — subsidies.
Table: broiler stocking density limits and example bird counts
Three density levels under EU Directive 2007/43/EC with example conversions to birds/m² at different slaughter weights. Indicative figures*.
33 kg/m² — basic level
Available to any producer without additional conditions. At a planned slaughter weight of 2.5 kg this gives about 13 birds/m². At 2.0 kg it gives about 16 birds/m². No special welfare documentation is required beyond standard regulations.
39 kg/m² — with documentation conditions
Requires welfare documentation from at least 2 previous cycles and good indicator results (mortality, footpad scores). At a slaughter weight of 2.6 kg this gives about 15 birds/m². Subject to inspection by the veterinary authority.
42 kg/m² — maximum stocking
Used with very good welfare indicators and after approval by the competent authority (local veterinary officer). At a slaughter weight of 2.8 kg this gives about 15 birds/m². Requires the highest standards of litter management and ventilation — the higher the density, the faster litter moisture rises.
Welfare programmes — about 30 kg/m²
Many poultry welfare subsidy programmes or buyer contract requirements specify stocking of about 30 kg/m², around 15% below the basic level (33 kg/m²). At a slaughter weight of 2.5 kg this gives about 12 birds/m². Check the terms of your contract or programme. Under the ARiMR ‘Animal welfare’ eco-scheme the broiler payment (an indicative 2026 rate of about PLN 0.2 per bird) is tied to, among other things, stocking up to 30 kg/m² and at least 6 hours of darkness per day — check the current terms with ARiMR.
The most common mistakes when planning broiler stocking density
A few mistakes come up repeatedly — worth knowing before you plan your next cycle.
Counting density in birds rather than in kg/m²
You place 15 chicks per m² and assume you have a good stocking density. The problem: at a slaughter weight of 2.8 kg that is 42 kg/m² — the maximum permitted density. If the birds grow faster than expected or arrive heavier, you could exceed the limit before slaughter. Always plan from the end — from the slaughter weight and the kg/m² limit.
Ignoring wet litter as the first warning sign
Wet litter is the earliest sign of overstocking — too much manure on the same floor area, ventilation cannot keep up, moisture rises. Wet litter also directly causes footpad dermatitis (lesions on the underside of the feet). More on the causes of wet litter in the guide on wet litter — causes and effects.
No welfare documentation when stocking above 33 kg/m²
Exceeding 33 kg/m² without maintaining the required documentation is a breach of veterinary regulations — regardless of how good your production results are. Records (logs, slaughter results, footpad scores) must be available for inspection throughout the required period.
Including non-accessible floor area in the calculation
Partitions, technical channels and other elements not accessible to the birds reduce the actual usable floor area of the house. If you calculate stocking density against the overall building footprint rather than the floor area accessible to broilers, the result will be too low — the actual stocking density will be higher than planned.
Frequently asked questions about broiler stocking density
What is the maximum stocking density for broilers in the EU?add
The basic limit is 33 kg/m² — available without additional conditions. It can be raised to 39 kg/m² after meeting documentation and welfare requirements (at least 2 previous cycles with good indicators). The absolute maximum is 42 kg/m² with very good welfare indicators and approval by the local veterinary authority. These limits come from Council Directive 2007/43/EC and the national legislation implementing it.
How do I convert kg/m² to the number of birds I place in the house?add
Formula: birds per m² = limit (kg/m²) ÷ planned slaughter weight (kg). Example: 39 kg/m² ÷ 2.6 kg = about 15 birds/m². Then multiply by the usable floor area of the house. At a slaughter weight of 2.5 kg and a limit of 33 kg/m² you get about 13 birds/m². Always calculate from the slaughter weight — that is what determines how many birds safely fit per m² throughout the cycle.
Why is stocking density measured in kg/m² rather than birds per m²?add
Because the birds grow — a day-old chick weighs about 40 g and a bird at slaughter over 2 kg. A fixed number of birds per m² would be too loose at the start and too tight at the end of the cycle. Measuring in kg/m² allows you to monitor actual density throughout the cycle and prevents exceeding the welfare limit before slaughter.
What happens when stocking density is too high?add
Overstocking causes wet litter, worse footpad condition (footpad dermatitis — lesions on the underside of the feet), slower daily weight gain, higher mortality and a lower welfare score at slaughter. In extreme cases it can lead to a compulsory reduction in stocking for the next cycle or loss of the right to apply higher limits (39 or 42 kg/m²). Footpad lesions are explained in the guide on footpad dermatitis — broiler footpad quality.
What stocking density do welfare programmes require?add
Most welfare programmes or buyer contracts require stocking of about 30 kg/m², around 15% below the basic 33 kg/m² threshold. At a planned slaughter weight of 2.5 kg that gives about 12 birds/m². Exact requirements depend on the specific programme or contract — check your agreement before each cycle. Remember too that, regardless of the law, in its 2023 scientific opinion EFSA recommends an even lower density (around ≤11 kg/m²) and slower growth — but these are recommendations, not a binding limit. More on welfare subsidies in the guide on poultry welfare — subsidies.
How does stocking density affect broiler footpad quality?add
Higher stocking density means more manure on the same litter area — the litter becomes wet faster, and wet litter damages the skin on the underside of the feet (footpads), causing lesions called footpad dermatitis. Footpad scores are recorded at slaughter and count towards welfare indicators — poor results can result in a compulsory reduction in stocking for the next cycle. The guide on footpad dermatitis — broiler footpad quality explains how to prevent this.
Sources & resources
- linkCouncil Directive 2007/43/EC laying down minimum rules for the protection of chickens kept for meat production (eur-lex.europa.eu)
- linkAviagen — Ross 308 Broiler: Performance Objectives (aviagen.com)
- linkPolish implementing regulation on minimum conditions for keeping farm animals — poultry (isap.sejm.gov.pl)
Track stocking density in DlaFerm.pl
Want kg/m² calculations and a digital flock record in one place? Create a free farm account or write to us.
Phone
+48 796 258 151