Chicken Coop Size Calculator (Australia)
Work out exactly how much coop and run space your flock needs — using Coop Castle's practical recommendation for backyard poultry.
How much space do backyard chickens need?
This is Coop Castle's practical recommendation for backyard flock planning — not a universal legal minimum. Under-sizing a coop is the single most common cause of feather-pecking, egg-eating, respiratory disease, and mite outbreaks — all of which cost more to fix than getting the footprint right on day one.
As a recommended starting point, plan for 0.4 m² of covered coop space and 1 m² of outdoor run space per adult bird. Heavy breeds (Australorp, Orpington) and confined setups should size up 20–30%; bantams can size down slightly. The calculator below applies the run-space ratio automatically based on your flock size — use the 0.4 m²/bird figure above as your coop-sizing rule of thumb.
Animal welfare and poultry-keeping requirements vary between Australian states, territories and local councils. For the nationally endorsed reference standards, see the Australian Animal Welfare Standards and Guidelines for Poultry, and check your state or territory government's animal welfare requirements.
For the full context — coop design, ventilation, fox-proofing and nest-box counts — see our complete coop design guide.
Each chicken needs at least 1 m² of outdoor run space and 0.4 m² of indoor coop space — Coop Castle's recommended starting point for backyard flocks (not a universal legal minimum; requirements vary by state, territory and council).
Overcrowded runs lead to bullying, feather pecking, stress, and disease. Use this calculator to check your run meets the standard.
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Why Space Prevents Problems
Chickens with enough space can escape bullies, establish pecking order naturally, and find their own food through foraging. Crowded birds have nowhere to go, leading to stress, pecking, and disease outbreaks.
Got your numbers?
Once you know your target coop and run size, use the full design guide to plan ventilation, roosting bars, nest boxes, and 1.6 mm predator mesh — everything the calculator doesn't cover.