Chicken Coop Size Calculator (floor area, perches, nests & run for laying hens)

Understanding the chicken coop size calculator — concept and principle

This calculator gives the minimum space and equipment for a flock of laying hens: coop floor area, perch length, nest boxes, feeder length, drinkers, littered floor and outdoor run. Use it when building or buying a coop, or when checking whether an existing coop can take more birds.

Space for 6 hens: with the default inputs the result is 24 m² run (4 m² each · 1 nest box).

How it is calculated

For n hens:

Coop floor area (m²) = n ÷ 9 (at most 9 hens per m² of usable floor); ft² = m² ÷ 0.09290304.
Perch length (m) = n × 0.15 (15 cm per hen).
Nest boxes = n ÷ 7, rounded up (one nest per 7 hens).
Linear feeder (cm) = n × 10.
Nipple drinkers = n ÷ 10, rounded up.
Littered floor (m²) = n × 0.025 (250 cm² per hen).
Outdoor run (m²) = n × run area per hen (4 m² is the free-range minimum).

The principle

These numbers are the legal minimums for laying hens in EU barn and free-range systems. They are set so that every bird can eat, drink, perch and lay at the same time without being blocked by others. Hens roost together at night, so perch length must fit the whole flock side by side. They feed as a group too, which is why feeder space is given per hen. Nest boxes can be shared because hens lay at different times. Litter lets hens scratch and dust-bathe, which are strong natural behaviours. Backyard keepers usually give more room than these commercial floors, because extra space reduces pecking, stress and mud.

Worked example

Default inputs: 6 hens, 4 m² of run per hen.

Floor = 6 ÷ 9 = 0.667 → 0.67 m², or 0.667 ÷ 0.0929 = 7.2 ft².
Perch = 6 × 0.15 = 0.9 m.
Nests = 6 ÷ 7 = 0.86, rounded up to 1.
Feeder = 6 × 10 = 60 cm; drinkers = 6 ÷ 10 rounded up = 1.
Litter = 6 × 0.025 = 0.15 m²; run = 6 × 4 = 24 m².

How to read the result

Treat every figure as a floor, not a target. For a small backyard flock many keepers give two to three times the coop area and add a second nest box so one hen cannot block laying. The run figure matters most for the birds' welfare and for the ground: too little space turns a run into bare mud. If you plan to add hens later, size the coop for the larger flock now.

Common mistakes

Counting the area under nest boxes or feeders as usable floor.
Fitting perches higher than the nest boxes, so hens sleep in the nests.
Building only the minimum and then adding birds.
Forgetting that the run area is per hen.

Keep in mind: These are EU commercial minimums, not a design standard for your site. Local rules on keeping poultry, distances to neighbours and bird-flu housing orders may also apply.

Frequently asked questions

How much space do 6 chickens need?

The legal minimum is about 0.67 m² of usable coop floor and 24 m² of run for free range, but backyard flocks do better with more.

How many nest boxes do I need?

One per 7 hens is the EU minimum; many keepers use one per 4–5 hens.

How should perches be spaced?

EU rules require at least 30 cm between perches and 20 cm from the wall, and perches must not sit above the litter.

Sources: Council Directive 1999/74/EC laying down minimum standards for the protection of laying hens, Article 4(1) · Commission Delegated Regulation (EU) 2023/2465, Annex II point 1(c)

Checked 9 Nov 2026. Council Directive 1999/74/EC laying down minimum standards for the protection of laying hens, Article 4(1) (feeders 10 cm, nipple drinkers 1 per 10 hens, 1 nest per 7 hens, perches 15 cm, 250 cm² litter, 9 hens per m² usable area); Commission Delegated Regulation (EU) 2023/2465, Annex II point 1(c) (free-range runs: 2,500 hens per hectare, i.e. 4 m² per hen).

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