Ilang litro ng tubig kada araw, lalo na sa tag-init?
Heat stress is the biggest avoidable backyard loss in a Philippine dry season, and the mechanism is water rather than shade. At 32°C a flock needs twice what it drinks at 21, and 32 is an ordinary coop at noon.
One flock, worked all the way through
The answer for these numbers
- The flock needs, litres a day
- 18.1 (17.0 to 19.2)
- Per bird, litres a day
- 0.362 (0.341 to 0.383)
- Heat multiplier
- 2.13x
- Over the storage period, litres
- 18.1 (17.0 to 19.2)
- Containers to carry
- 1
- The water in the drum
- Intake drops. This is the ordinary Philippine failure, and it costs you the volume you carried.
| Coop, °C | Multiplier | Litres per kg of feed |
|---|---|---|
| 21°C | 1.00x | 1.60 to 1.80 |
| 24°C | 1.21x | 1.93 to 2.17 |
| 26.6°C | 1.42x | 2.28 to 2.56 |
| 28.3°C | 1.58x | 2.53 to 2.85 |
| 30°C | 1.76x | 2.82 to 3.17 |
| 32°C | 2.00x | 3.20 to 3.60 |
| 35°C | 2.41x | 3.86 to 4.35 |
Aviagen, Ross Broiler Management Handbook 2025, p.57: 6.5% more water for every degree above 21°C, compounding. Read the middle rows twice. PAGASA puts the Philippine mean annual temperature at 26.6°C and the warmest month at 28.3°C, so the country's AVERAGE day is already carrying a 43% premium over the anchor, and an open-sided coop in afternoon sun runs several degrees above ambient on top of that.
Read the multiplier column, not the litres. It is the same flock and the same feed in every row; the only thing changing is the coop. Aviagen, Ross Broiler Management Handbook 2025, p.57.
Why the 6.5% compounds, and why that is the whole tool
Aviagen writes that water need rises "by about 6.5%" for each degree above 21°C, and that sentence reads two ways. Compounding it (1.065 to the power of the degrees above 21) doubles consumption at 32°C. Adding it up in a straight line would need 36.4°C to double, which is hotter than most of the Philippines ever gets, so the handbook's own next sentence about tropical heat doubling intake could never come true on its own figure. This tool compounds, because that is the reading the source is consistent with, and every figure on the page moves if you disagree.
Which means the sentence to take away is this one: a flock at 32°C needs twice what it drinks at 21°C, and 32°C is an ordinary bakuran coop at noon. Not a heatwave, not a record. Noon. Heat stress is the largest avoidable backyard loss in a Philippine dry season and the mechanism is water rather than shade, kasi a bird sheds heat by panting and panting is evaporation.
The drum is the second problem
A keeper who correctly doubled the volume can still have birds that will not drink it. Water above 30°C reduces intake, and a black plastic drum or an uncovered line in Philippine sun is past 30 by ten in the morning. Bigyan mo ng lilim ang drum, and refill at midday rather than at dawn. That advice costs nothing and appears on no competing Philippine page.
| Water, °C | What happens |
|---|---|
| < 5 | Too cold. Intake drops. |
| 18 to 21 | Ideal. |
| > 30 | Intake drops. This is the ordinary Philippine failure, and it costs you the volume you carried. |
| > 44 | Birds refuse it outright. |
Aviagen Table 2.2, p.23. This is the half nobody prints: a keeper who correctly doubled the volume can still have birds that will not drink it, because a black drum or an uncovered line in Philippine sun is past 30°C by mid-morning. Shade the drum, and refill at midday rather than at dawn.
What is in the water
This one is a lookup rather than a calculation: a well or a barangay supply either clears these or it does not. Most of it comes back on an ordinary water test from a provincial DA office or a private lab. The coliform row is the one to ask for by name.
| What is measured | Good | Unacceptable |
|---|---|---|
| Total dissolved solids | < 1,000 ppm | > 5,000 ppm |
| pH | 6.5 to 8.5 | Outside that range |
| Chloride | < 250 ppm | > 500 ppm |
| Nitrate nitrogen | < 10 ppm | > 10 ppm |
| Iron | < 0.3 ppm | > 0.3 ppm |
| Coliforms | 0 CFU/mL | > 0 CFU/mL |
Aviagen, Ross Broiler Management Handbook 2025, Table 7.2, p.109. This is a lookup for a well or a barangay supply, not something the calculator computes. A water test from a provincial DA office or a private lab reports most of these; the coliform row is the one to ask for by name.
What the grid assumes
- Water is worked out from feed, not from a bird count: 1.6 to 1.8 litres for every kilo the flock eats, at 21°C. Aviagen, Ross Broiler Management Handbook 2025, p.57.
- You entered 5 kg a day for the WHOLE FLOCK of 50 birds, which is 100 grams a bird. If that second figure looks wrong, the first one is per bird and the answer below is out by a factor of 50.
- 33°C is 12 degrees above the 21°C anchor, which multiplies the requirement by 2.13. For context, PAGASA puts the national mean at 26.6°C and the warmest month at 28.3°C, so an ordinary Philippine day is already carrying a premium here.
- Aviagen writes that water need rises "by about 6.5%" for each degree above 21°C, and that sentence reads two ways. Compounding it (1.065 to the power of the degrees above 21) doubles consumption at 32°C. Adding it up in a straight line would need 36.4°C to double, which is hotter than most of the Philippines ever gets, so the handbook's own next sentence about tropical heat doubling intake could never come true on its own figure. This tool compounds, because that is the reading the source is consistent with, and every figure on the page moves if you disagree.
- At this temperature the flock needs at least twice what it drinks at 21°C. That is the case Aviagen describes in one line and never puts a number on: "in tropical areas, prolonged high environmental temperatures will double daily water consumption". It happens at 32°C, which is an ordinary coop at midday.
- Containers are counted off the WORST case, 19.16 litres a day over 1 day(s), and rounded up: 1 container(s) of 20 litres. Under-watering a flock in Philippine heat is not symmetric with over-watering it, so the rounding goes the safe way.
- Water above 30°C reduces intake and birds refuse it above 44°C (Aviagen Table 2.2, p.23). A black drum or an uncovered line in Philippine sun is past 30°C by mid-morning, so a keeper who correctly doubled the volume can still have birds that will not drink it. Shade the drum and refill at midday.
What it does not cover
- The 1.6 to 1.8 litres per kilo of feed is an Aviagen broiler figure, from the Ross Broiler Management Handbook 2025. It is used here for layers and native chicken as well, and the page says so rather than hiding it. A RATIO of water to feed carries across bird types far better than an absolute litres-per-bird figure does, which is the whole reason this tool takes feed intake instead of a bird count and an age.
- The figure is what the flock NEEDS, not what your drinkers can deliver. A nipple line at low pressure, a bell drinker that empties by noon, or a drum in the sun are all ways to meet this number on paper and not in the coop.
- Below 21°C the multiplier is held at 1.0 rather than run backwards. Aviagen publishes no reduction figure below its own reference, and inverting an increase would be inventing one.
- The 250 to 300 mL per hen per day that circulates online has a parent after all. DA Regional Field Office II's Table I puts a layer at 7.9 gal/100 birds/day at high temperature, which is 299 mL. It is an extension leaflet from 2004 written for White Leghorns and indexed to feed intake and egg output rather than to ambient temperature, so it is not used as this tool s coefficient. It is named because saying no figure exists would now be wrong.
Why this asks what your flock eats instead of how many birds you have
Because the per-bird figure that does exist is narrower than it looks. DA Regional Field Office II publishes a water column for layers, 5 to 7 gallons per 100 birds a day at moderate temperature and 7.9 at high, which works out at 299 mL a hen a day at the top row. It is a 2004 extension leaflet written for White Leghorns, and it is indexed to feed intake and egg output rather than to ambient temperature, so it cannot be moved to a Philippine afternoon without assuming the thing you wanted it to tell you. What Aviagen publishes instead is a RATIO of water to feed, and a ratio carries across bird types far better than an absolute per-bird figure does. So the tool asks for the one number a keeper can actually weigh in an afternoon. It is a broiler figure and the page says so rather than hiding it.
The Philippine reality gap
Every coefficient here is imported. Aviagen measured a broiler house, not a bakuran, and the 21°C anchor is a temperature a Philippine coop reaches at dawn in January and not again. PAGASA puts the national mean at 26.6°C and the warmest month at 28.3°C, so the AVERAGE Philippine day already carries a 43% water premium over the anchor before the coop's own heat load is counted, and an open-sided coop under afternoon sun runs several degrees above ambient. One Philippine figure does exist and it is narrower than it looks: DA Regional Field Office II's Table I carries a water column of 5 to 7 gal/100 birds/day at moderate temperature and 7.9 at high, which is 299 mL a hen a day at the top row. It is a 2004 extension leaflet for White Leghorns, not a national standard, and it is stated against feed and egg output rather than against ambient. So it anchors the folklore figure without replacing the ratio, and this tool still asks what your flock eats rather than telling you what it drinks.
Where these numbers come from
- Aviagen, Ross Broiler Management Handbook 2025
aviagen.
com read on August 13, 2026imported - PAGASA, Climate of the Philippines
pagasa.
dost. read on August 13, 2026Philippinegov. ph