By Tom Tabler, PhD
Extension Professor
Mississippi State University Extension Service, Poultry Science Department
Mississippi State, MS

However, on many farms I visit, growers don’t always understand the difference between pressure and volume or the important roles they play in meeting this objective.

Water pressure and volume are both critical to the health, and even survival, of a flock. I’ve found the simplest way to understand the difference between pressure and volume is this: Pressure is how much force is needed to get water where it’s going; once it’s there, volume is how much water is needed to meet the flock’s demand.

Most integrators today require at least two water sources on every poultry farm - two wells or one well plus community water. They also provide guidelines on how many gallons of water per minute should be delivered.

"I don’t know"

To meet this need, many growers drill wells between the chicken houses so the supply is conveniently near the demand and to avoid long runs of pipe that can cause pressure loss. Yet, whenever I visit a farm and suspect water is adversely affecting bird performance, it’s difficult to get pertinent information. The first two questions I ask are:

• What size is the supply line from the well to the chicken houses?
• What size pump is in the bottom of the well?

More often than not, the answer I get to both questions is, “I don’t know.”

I’ve been on farms during summer afternoons where the house farthest from the well would only have about half of the cool-cell pad actually getting wet because there wasn’t enough water pressure or volume to reach the end of the line at that house. It’s hard to fix something if you don’t know it’s broken, and sometimes, growers simply don’t know something’s broken.

Undersized pump or supply lines

Using an undersized pump is a common mistake. If you have a pump capable of pumping 50 gallons per minute (gpm) but the total water demand by all your chicken houses is 70 gpm, you are going to have problems.

Another common mistake is utilising an undersized supply line from the well to the chicken houses. If the water demand on the farm is 60 gpm and there’s a 2-inch supply line from the well to chicken houses, you cannot provide 60 gpm! A 2-inch pipe can carry only about 48 to 50 gpm.

Growers also often fail to increase the size of the supply line after they add additional houses. A four-house farm may be fine with a 2-inch supply line. However, if you build two additional houses and don’t upgrade to a 3-inch line or add an additional water source, there will be water-restriction issues.

Recently, conventional thinking has been that a typical 40-foot x 500-foot broiler house requires about 2 gpm for drinking and about 8 gpm for the cool cells (a total of about 10 gpm per house). However, chicken genetics change every year. Chickens today eat and drink more than they did just a few years ago. I’m pretty conservative, so I feel better recommending 3 gpm for drinking and 9 gpm for the cool cells. PVC pipe is inexpensive compared to what it will cost if you undersize your supply line and shortchange yourself on water.

Large birds need more water

Trouble with the water supply can also occur when growers switch from growing small birds (4.5 pounds or less) to large birds (9.5 pounds or more) without upgrading the supply line. Growing larger birds requires more water for both drinking and cooling. Improved cooling is typically achieved by adding an additional 20 feet or more of cool cell to each side of your house, which requires more water, and an additional one or two tunnel fans.

If you have an older farm that may only have a ¾-inch or 1-inch supply line, that line will not adequately handle the water demands of larger birds during later grow-out stages. You may need to increase the size of the well pump and the supply line in order to meet demands.

I can’t emphasise enough the importance of meeting peak water demand in summer with big chickens on the farm. You may only reach peak demand once or twice a year, but you must have the ability to do so. Otherwise, drinking and/or cooling water will be limited, which could prove disastrous with large birds in hot weather.

Realise that water filters further restrict flow. Water pressure will decrease approximately 5 pounds per square inch for each in-line water filter the water passes through. Pumping water uphill also results in a significant pressure loss before water ever reaches the houses; therefore, well placement is an important consideration.

Know peak demand

Know your peak 24-hour water demand. If there are big chickens on the farm, I’ve found this peak is usually in July or August. If your controller can record hourly data, watch for plateaus in water use during the hottest part of the day when demand is greatest. They could indicate the pump, supply, supply line or perhaps a combination of all three are undersized.

Water lines for drinkers should come off the supply line first before line(s) supplying cool cells and possibly foggers. Cool-cell water should not come off the supply line first because it will starve the drinker line. If there’s not a water meter on your cool-cell line, I advise adding one to track cool-cell water use. On hot days with big chickens, cool cells can use as much or more water than drinkers.

It should go without saying that the water supply should be tested for mineral concentrations and bacterial contamination to ensure it’s safe for poultry to drink.

Here’s a list that sums up the variety of problems that can affect water pressure and volume:

• Poor planning
• Undersized main line and/or water meters
• Distance between farm and well or municipal line
• Changes in elevation
• No municipal supply available
• Insufficient well capacity
• Failure to maintain drinker system
• Not checking water availability before building
• Too many houses for the amount of water available
• Adding additional houses or retrofitting beyond water supply capability
• Failure to regularly test water supply
• No backup plan in place should something happen to interrupt the water supply

5-gallon bucket test

A quick estimation of how much water you can deliver is the 5-gallon bucket test. Fill a 5-gallon bucket with water from the control room and time how long it takes for the bucket to fill. The bucket will fill slower with birds in the house. A quick estimation is:

• 5 gallons in 10 seconds = 30 gpm
• 5 gallons in 15 seconds = 20 gpm
• 5 gallons in 30 seconds = 10 gpm

Over the years, I’ve had to tell a lot of growers their supply line was too small or their well pump was undersized. One of these conversations took place in September 2017, so the problem is still out there today, especially on many older farms trying to grow birds larger than the farm was designed for.

It’s easy to ignore the water supply if the power is on and the well pump is running, but this is a mistake. Everything about managing a poultry farm is important, but nothing is more important than having enough water.

There is information out there to help you properly size for pressure and volume1,2,3,4. I recommend you take advantage of it! Understanding water pressure and volume will help keep your flock safe, healthy — and maybe even alive — during critical periods.

References

1. Barrett J, Tabler T. Private water well placement and sizing for poultry production. Mississippi State University Extension. Pub. 2953. 2016 May.

2. Czarick M. Broiler farm water usage and pipe sizing rules of thumb. Poultry Housing Tips. University of Georgia Cooperative Extension Service. 2007 May.

3. Donald J, et al. Key water factors for broiler production. Alabama Poultry Engineering and Economics Newsletter. Auburn University. 2000 September.

4. Tabler T, et al. How total farm water pressure and volume affect commercial poultry production. Mississippi State University Extension. Pub. 3058. 2017 March.