How big should the kulungan be?

PNS/BAFS 262:2018 § 6.3.1, a fixed building: 10 birds/m² for broilers, 6 birds/m² for layers and native chicken. So 20 native na manok need about 3.3 m² of floor inside, roughly a 1.8 by 1.8 metre kulungan. Layers and native get more room per bird than broilers do, kasi they live in that kulungan for months rather than for the few weeks a broiler is there.

The bit nobody else tells you about broilers

PNS states the broiler limit twice: 10 birds/m² or 17 kg/m². Those two land on the same answer at exactly 1.7 kg per bird, which is the top of the liveweight Philippine broiler farms grow to. Under that weight, bilangin mo ang manok. Over it, the weight rule takes over, so a 2.5 kg bird needs about 47% more floor than the familiar rule of thumb gives it.

Above 3 kg the calculator refuses to answer rather than guess. Its own words: "Above 3 kg liveweight there is no published stocking figure for an open-sided coop with no fans or cooling. Aviagen's advice is not to grow birds that heavy in one. This tool stops here rather than guessing."

Feeders and drinkers

Trough space is a Penn State Extension small-flock figure, and the drinker ratios are Aviagen's post-brooding ones (Ross Broiler Management Handbook 2025). Both are imported, and equipment ratios travel better than density figures do: a nipple delivers the same water sa Nueva Ecija at sa Iowa.

Feeder space assumes the whole flock eats at once, which is what happens in a bakuran. A commercial chain feeder runs continuously and the birds eat in shifts, which is why Aviagen publishes a lower 2.5 cm per bird.

Pugad at patungan, for inahin

The same standard says not more than 5 birds per nest hole and 31 cm of perch per hen. Count the inahin only: the tandang take floor space but no pugad.

Roosters need floor space but not nests, so the tandang are counted in the floor-area grid and not in this one.

If the manok actually go outside

This is the free-range standard, so it has a range in it: 2 birds/m² for broilers, 1 bird/m² for layers and native chicken (PNS/BAFS 262:2018 § 6.4.3). Kung nasa loob lang lagi ang alaga mo, skip this table. The floor area above does not change either way.

The shade column is the standard written as published: 8 to 16 m² per 1,000 birds. At bakuran scale it reads as almost nothing, because the figure was written for 1,000-bird units. Treat it as a floor, not as a target.

Where these numbers come from, and what most guides use instead

Ask this online and you get four square feet per bird, every time. That figure is American, it is written for a closed henhouse in a temperate winter, and whoever wrote it has never stood in a bakuran in May. The Philippines has a standard of its own with a real number in it: PNS/BAFS 262:2018, Free Range Chicken, drafted by a technical working group that included BAI and Central Luzon State University. Halos walang gumagamit nito. Every table above is that standard, computed for the flock sizes a backyard keeper actually has.

The standard also sets a harvest floor for a flock that genuinely lives outside: § 6.5 puts the earliest harvest at day 52 for free-range broilers and day 90 for native chicken. Worth knowing bago ka mangako sa isang suki. Anybody quoting you a 12 by 12 inch nest box is quoting Penn State, hindi ang PNS. 262 counts birds to a hole and never says how big the hole is, which is why the nest table above stops where it does. The dimension is not missing from the Philippines, only from this standard: the layer code, PNS/BAFS 312:2021 § 6.5.2, asks for 35 cm in every direction per hen. Nothing above is computed from it, kasi 262 ang tinatakbo ng buong page na ito.