Early Feed Intake and Bird Performance
Importance of Early Feed Intake Time to Consume No. of Farms Av. Daily Gain Wt. at 49 days Adj. Feed < 17 19 0.103 5.05 2.04 17 - 19 33 0.101 4.95 2.10 > 19 42 0.100 4.90 2.18
Feed intake is the single most important factor in determining growth rate of commercial broilers and turkeys. The data in Table 1 were obtained from industry sources and show that birds consuming feed the fastest weighed the most at processing and converted feed best. These data show what experienced growers have known for some time — flocks that do the best tend to be active and consume starter feeds quickly.
It is also important to realize that feed intake is most important in the youngest birds. Figure 1 illustrates this fact. Most of the energy and nutrients consumed by birds younger than four weeks goes toward growth. After four weeks the majority of energy and nutrients goes toward maintaining the bird’s body. This means that if energy and nutrients are restricted early in the bird’s life, it will likely never catch up to birds that were provided a good start.
In addition, flocks in which the majority of birds start well tend to be relatively uniform in size, making management and optimum results easier. Flocks with the highest feed intake will almost always have the highest average daily gain and weigh most at processing.
Table 1. Early Feed Intake and Broiler Flock Performance
1.5 lbs of Starter
(Days)
(lbs/day)
(lbs)
Conversion 
Figure 1. Energy and Nutrient Utilization as Broilers Grow
Understanding Feed Intake
Achieving maximum feed intake is much more complicated than just making sure your feed pans have feed. The amount of feed a bird consumes can be limited by four factors: physical limitations, bird physiology, feed availability and water availability.
Birds start eating because of a lack of fullness in certain sections of their gut. While some farm animals start eating for the same reason, certain farm animals (like cows) will eat until they are full (if adequate feed resources are available) and then rest while the feed digests. However, chickens and turkeys tend to be nibblers. They will fill their crops, wait until some feed leaves and then fill the crop again. Yet there are physical limitations to the amount of daily intake a bird can handle. In addition, the amount of feed birds eat is based on the passage of non-digested feed from the digestive tract. The slower the rate of passage, the greater the amount of intake restriction.
The physiological limit to feed intake is controlled by the bird’s energy requirements for growth and body maintenance. If feed is available and gut fill or other physical factors do not limit intake, then intake is determined by the bird’s demand for energy. If birds are being fed a low energy diet, they will tend to eat more of that diet than if they were fed a higher energy diet. This situation is similar to that in humans and other species. How many of us as children ate candy and did not want to eat our supper? The reason we did not want to eat supper is the candy met our energy needs. What does this mean for us as poultry growers? It means that anytime we provide birds with an additional source of energy, we could reduce feed consumption and, in turn, growth.
If feed is unavailable then feed availability obviously limits intake. The lack of feed could be due to a mechanical problem, a feeder line set wrong or a missed feed delivery. Regardless, it is important to ensure that birds always have access to feed.
Water is, without question, the most essential nutrient. Without adequate water birds can survive a few days, but do not do well. This is because of the birds need for water and because the availability of water affects feed consumption. When kept at 70°F birds consume about twice as much water as feed on a pound-for-pound or weight-for-weight basis. Every effort must be made to insure the availability of an adequate amount of water by providing adequate drinker space as well as maintaining proper drinker height, pressure and flow rate throughout the entire water system.
Management Considerations
On-farm management practices can cause feed intake to vary significantly across flocks and different housing set-ups (tunnel, conventional, dark-out, etc.). Even though growers may be feeding the same feed and following the same “general” management guidelines for their specific complex, feed intake will be affected by individual management styles, bird genetics, health status of the flock and the environment the birds are subjected to over the life of the flock. As growers, we must do our best to 1) provide birds with adequate access to feed and water, 2) reduce environmental stress due to temperature extremes, ammonia levels or wet litter and 3) minimize disease challenge. The only sure-fire way for growers to be confident all these management criteria are being met is to spend time in the chicken house. Automatic controllers are great, but they do not take the place of someone being in the chicken house. Numerous trips per day to the chicken house are required if you are going to catch a water spill, find a cross auger hung up, re-wire a feed motor or adjust the ventilation rate before major problems occur. Technology has removed much of the manual labor from growing chickens, but it has not removed the need for a person watching over growing chickens. It has been my observation from my early days as a broiler service technician right up through today that, as a general rule, how well a grower does on a flock of birds is directly proportional to how much time he spends in the poultry house. While there are exceptions, generally, growers who do the best spend the most time in the chicken house. Growers that spend time in their houses catch potential negative situations, maintain a more uniform environment by making almost constant little adjustments and fix little problems before they become big ones. Although taking care of these small things may seem like busy work, the cumulative effect over a six-to-eight-week growout may be the difference between being on top of the list and being average or below. Every grower is different, and some have off-farm jobs that prevent them from “living” in the chicken house. However, be aware that raising chickens or turkeys is like most other endeavors in life. The more time and effort you are willing and able to put into a project, the better you are at that project.
Regardless of how many visits are made on a daily basis, certain things should be checked with each visit to the poultry house. Always check feeders and drinkers to make sure that feed pans have feed and drinkers have water. Also, feeder and drinker height must be adjusted throughout the flock to provide easy access to feed and water at all times. Feed intake will not be optimum if a bolt in the auger blows a circuit breaker or overheats a feed line motor and no one discovers the problem for four hours or longer. Even more dangerous is an in-line water pressure reducing valve failing on the hottest day of August and the problem not discovered until birds start dying. Almost constant vigilance is required to prevent little problems from becoming major disasters.
Temperature, humidity and ammonia levels should also be checked on each visit and necessary adjustments made. Birds under stressful conditions are not as efficient at converting feed to meat. When responding to environmental stress, birds will have increased levels of stress hormones in the body. Also, gut motility and nutrient absorption are decreased while body energy reserves are used to combat the stress and thereby, unavailable for growth and weight gain. The type of stress can have a major impact on feed intake levels. Acute stress, which lasts only a short period and is then corrected, may decrease feed intake for only a short period and have minimal performance effects. An example is running out of fuel and chilling the house until more fuel is delivered and the brooders are re-lit. Chronic stress, however, such as excessive ammonia levels
throughout the life of a flock can have serious detrimental effects on both feed intake and performance. Stress may also lead to a weakened immune system and increased disease susceptibility which can decrease feed intake. In addition, when the bird is under stress or disease challenge, the bird uses energy and nutrients to mount an immune response rather than grow.
Summary
Feed intake is the single most important factor regulating performance of agricultural animals. Feed intake controls the rate of output of all animal products and is the common denominator of efficiency, regardless if the output is meat, eggs, or reproduction. While numerous factors influence feed intake, as growers we control our own destiny when it comes to on-farm management practices. We must provide access to feed and water at all times. Feeder and drinker height must be adjusted and maintained at the proper level during the entire flock. Temperature, humidity, ventilation, and ammonia must be kept within acceptable ranges; otherwise, feed intake and flock performance will suffer. Spending time in the chicken house is the only way to guarantee that all these needs are being met. Automatic controllers are marvelous inventions and allow us more flexibility than ever before. However, don’t let them take the place of you spending time in the chicken house. Today there is a substitute for almost everything except you being in the chicken house.
Reference
Donald, J., M. Eckman and G. Simpson. 2002. The impact of management on infectious diseases in broilers. The Alabama Poultry Engineering and Economics Newsletter No. 16, March, 2002.
