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Brooding Chicks and Poults: Environmental Critical Control Points

Rabu, 3 September 2008

Farm management during the early brooding stage in the life of the chick or poult will determine whether they will reach their full potential. Every hour that a chick’s or poult’s environment is less than optimum reduces growth rate and increases feed conversion ratio and that loss recovered by the end of the growout (Dozier and Donald, 2001). Costs to both the grower and the integrator will be high if a proper brooding environment does not ensure that birds get off to a good, healthy start. The focus of this article will be on how to best meet the needs of the broiler chick and turkey poult brooding.

Brooding the Broiler Chick

The objective in brooding chicks is to provide growing birds a comfortable and healthy environment, efficiently and economically (Vest, 1997). Temperature (particularly of the floor), ventilation rates, humidity, litter conditions, dust and gas levels are all environmental critical control points that growers must monitor and manage. Failure to properly manage these environmental critical control points during the brooding period will likely result in lower economic returns.

The body temperature of a day-old chick is about 3° F below that of an adult, but by five days of age body temperature has reached 106° F, the same as the adult (Vest, 1997). Newly hatched chicks have little or no ability to regulate their own body temperature and depend on the grower to provide an ideal growing environment (Dozier and Donald, 2001). Yet the ability of chicks to regulate their body temperature has a direct impact on the birds ability to grow efficiently. This means that exposing chicks to temperatures too high or too low will result in energy and nutrients being expended to cool the bird by panting or to warm the bird
by heat production (Lacy, 2002). However, ever increasing fuel costs usually mean that over heating of chicks is a rare occurrence.

When a newly hatched chick is placed in a cool environment, its internal body temperature begins to drift downward toward the environmental temperature and may reduce the growth efficiency of the bird. Keep in mind, that in broiler houses, floor temperature is often 5 to 15° F below air temperature (Lacy, 1997). The temperature of the broiler house floor during brooding is more important than air temperature, since chicks are in direct contact with the floor. Even fairly brief exposure to cool floors can adversely affect chicks.

In one research experiment, 175 newly hatched chicks were placed in either a constant temperature of 95° F or were exposed to a temperature of 65° F for two hours and then at a constant 95° F. After four days the internal temperature of chicks subjected to that brief cold exposure was only 100.5° F, versus 102° F for the control group reared at a constant 95° F (Dozier and Donald, 2001).

Normal development of the digestive, circulatory, nervous and immune systems of the chick depends on the bird using the nutrients and antibodies provided by the yolk sac to ready these systems to begin getting nutrients from the feed (Dozier and Donald, 2001). If chicks are chilled, nutrients that might have been used for body development are used to maintain body heat. Chilled chicks also tend to huddle together, and most do not seek out feed or water, so a number of birds may die. The performance of the chicks that survive chilling is likely to be limited due suppressed digestive or immune system functions. Periods of extended cold stress force the chick to begin breaking down the carbohydrates and fats in its own body tissues to maintain body heat, since it is unable to acquire enough from the feed alone.

Deaton et al. (1996) brooded chicks at starting temperatures of 95°, 90°, 85°, or 80° F, then decreased brooding temperatures by 5° F each week for three weeks. After three weeks temperatures were held constant at 70° F. At three weeks of age body weight and feed conversion were better for the chicks brooded at the warmer temperatures (Table 1). Since low environmental temperatures cause increased feed intake and higher oxygen demand, chilled birds are in an ideal situation to develop ascites (Table 2) (Lacy, 1997). University studies have shown increases in ascites as high as 11% in broilers raised in too-cool brooding environments (Dozier and Donald, 2001).

Table 1. The effect of brooding temperature on body weight and feed conversion of broiler males at 3 weeks of age1.

Temperature ºF

Body Weight
(lbs)

Feed Conversion

Week 1

Week 2

Week 3

95

90

85

1.76

1.35

90

85

80

1.75

1.37

85

80

75

1.74

1.39

80

75

70

1.66

1.42

1 Adapted from Lacy (1997)

Table 2. The effect of brooding temperature on mortality of broiler males at 6 weeks of age1.

Temperature ºF

Total
Mortality
(%)

Ascites
Mortality
(%)


Week 1


Week 2


Week 3

95

90

85

2.29

0.83

90

85

80

3.12

0.83

85

80

75

1.67

0.62

80

75

70

4.79

2.50

1 Adapted from Lacy (1997)

The proper temperature for brooding broiler chicks will depend on the system being used. However, it is important to realize that supplemental heat will be required even in the summer and especially at night (Dozier and Donald, 2001). Brooding systems have been classified various ways. Dozier and Donald (2001) suggest that forced air furnaces and brooders are the two basic methods of providing heat for chicks, while Lacy (2002) mentions three methods of warming chicks ( warm room brooding, hover (or pancake) brooding and radiant brooding). Lacy (2002) lists recommended temperatures for each brooding method (Table 3).

Table 3. Recommended Temperatures for Broilers

Weeks
of Age

Brooder Type

Warm Room
ºF

Hover
ºF

Radiant
ºF

1

88

90

85-88

2

83

85

82-85

3

78

80

77-80

4

73-76

75-78

73-76

5

70-73

70-73

70-73

6

65-70

65-70

65-70

Adapted from Lacy (2002)

Furnace heat (or warm room brooding) is more difficult to manage than pancake or radiant brooders for two primary reasons. First, furnaces produce warmth by producing heated air. This means that the floor must be warmed from hot air, which can require a long period since hot air rises, and temperature stratification can develop with hot air at the ceiling and cold air at the floor. Mixing fans near the ceiling work well to break up stratification and should be utilized to increase floor temperature and decrease gas usage (Dozier and Donald, 2001). Second, furnace heat does not allow chicks to select a comfort zone. The entire room is heated and chicks must grow at the selected temperature. This means that there is little room for error with furnace heat; the temperature maintained must be exactly what chicks need, since they can not find a warmer or cooler area (Lacy, 2002).

Both pancake and radiant brooders allow chicks to move toward or away from the heat source to seek a comfortable temperature (Lacy, 2002). Most of the heat from these brooders is in the form of infrared light, which heats objects instead of heating the air (Dozier and Donald, 2001). Floor temperatures under the brooder will be higher than the surrounding air temperature, so that heat is delivered where it is most needed … at chick level (Dozier and Donald, 2001). In recent years radiant brooders have become popular, since they have been shown to reduce fuel costs by 15 to 30% as compared to pancake brooders and forced air furnaces (Lacy, 2002).

Although warmth is a critical need for newly hatched chicks, these young birds also require a minimum amount of ventilation during the brooding period. Ventilation is necessary to add oxygen, remove harmful gases (carbon dioxide and ammonia) and to remove moisture added by the birds. As the ventilation system operates, cool fresh oxygenated air is brought uniformly through the inlets and jetted along the ceiling toward the center of the house, mixing with hot air already in place and sending it back toward the floor. At the same time, humidity, ammonia, dust and carbon dioxide are removed from the house while the exhaust fans are in operation. Without adequate ventilation, ammonia, humidity and the lack of oxygen can reduce performance and increase mortality.

Many growers underestimate the effects of ammonia on flock performance. Ammonia levels of 25 ppm (barely detectable by the human nose) have been shown to depress growth by 4 to 8% and increase feed conversion by 3 to 6%. Just 5 ppm ammonia has been shown to irritate and injure the protective lining of the chick’s respiratory system, causing the bird to be more susceptible to respiratory disease. If growers wait until ammonia levels are high enough to be detected by odor or a sense of smell, some damage has already occurred. To minimize ammonia problems it is important to provide adequate ventilation and control moisture in the poultry house (Lacy, 2002).

Birds add moisture to the poultry house environment by respiration and by feces excretion. Since birds, like all animals, exhale warm moisture laden air, respiration increases the humidity of the inside environment, which can, if not removed, cause increases in litter moisture. Broilers consume about one and a half to two times as much water as feed, but they only retain about 20% of the water, thus the other 80% is excreted (Dozier and Donald, 2001). A broiler chick excretes about 0.06 ounces of water per hour in the first week, and about 0.11 ounces per hour in the second week (Dozier and Donald, 2001). Assuming birds are provided 23 hours of light per day, this would mean that during the first week a flock of 20,000 birds would add slightly over 1,509 gallons of water to the poultry house environment. During the second week the same flock would add about 2,767 gallons of water to the poultry house. The amount of water excreted increases with bird age and weight. This, in part, is why we must increase ventilation rates as the birds age — to compensate for the additional water being added to the litter. If litter moisture and humidity are not removed, litter moisture increases, leading to damp, caked or wet litter conditions. However, the level of humidity also appears to be critical for poultry (Vest, 1997). Results show that increased relative humidity leads to depressed feed consumption, independent of temperature (Table 4) (Vest, 1997).

Table 4. Feed consumption in grams as influenced by relative humidity in 4 week old broilers.1


Temperature
(ºF)

Relative Humidity (%)

37

49

56

67

73

82

Feed Consumed (grams)

90

44

14

81

56

50

72

61

47

1 Adapted from Vest (1997)

Be sure temperature sensors are located in the proper position and minimum ventilation rates correctly match the age of the birds. If temperature sensors are too close to the brooders, it can be difficult to obtain the proper, uniform floor temperature. If sensors are placed too high off the floor, they will not allow the heating system to operate properly, since the floor and air directly above the floor will cool much quicker than air three to four feet above the floor. At placement, temperature sensors should be three to four inches above the floor and then adjusted upwards as the birds age. Adjust the override thermostats so that they are high enough above the set point temperature that they will not chill the chicks by overriding the minimum ventilation timer and running the ventilation fans when they are not needed. A properly working ventilation and heating system will not only maintain the desired air and floor temperature, but also provide sufficient air exchange, control moisture, dust and ammonia levels as well as maintain the desired litter conditions. However, it can only do what you tell it to, and you must continually tell it something different as weather conditions change, the birds age and environmental conditions inside the house change. Thus, there is no substitute for the grower spending time in his houses.

Brooding the Turkey Poult

Brooding turkey poults is as much of an art as a science. Each flock is different based on a variety of factors, and excellent husbandry skills are essential to be able to evaluate poult behavior and determine their needs. Compared to broiler chicks, all poults would be considered very difficult to start. Like broiler chickens, turkey genetics have improved the bird over the past 10 to 15 years but has required a higher level of management skill from growers to obtain optimum results. Wojcinski (N.D.) listed five critical control points she believes, if implemented correctly, will result in a healthy, vigorous, uniform flock with feed conversions and average daily gains which meet or exceed industry standards. These include:

• Barn preparation for poult arrival
• Poult quality assessment
• Brooding temperatures
• Barn ventilation
• Feed and water availability and quality

Many different kinds of stressors are present within the commercial turkey production environment. The one most often overlooked is that of the growth itself (Wojcinski, N.D.). When growers were asked when the stress of growth was the greatest, most replied that it is around 15 weeks of age. However, the tom poult is actually growing the most rapidly at three weeks of age (Wojcinski, N.D.). It is at this time that the percent increase in metabolic body weight is the greatest. Early in the brooding period when the poults are growing so rapidly, they are very susceptible to the adverse effects of poor ventilation management, poor feed quality and disease challenges. Even minor inadequacies during this period will be reflected in decreased growth and performance. This is why the first three weeks of a poult’s life are crucial to its future performance (Wojcinski, N.D.). Optimizing the poult’s environment at this time is one of the best investments a producer can make.

One of the most critical factors in managing the poult’s environment is the proper temperature in the house and under the brooders. While having the air and floor temperature too cool is always a concern, a temperature that is too warm is also detrimental. Having the temperature too high can quickly dehydrate poults, with small poults being the most susceptible to the effects of overheating (dehydration and flip-overs) (Wojcinski, N.D.). Litter temperature is more critical than air temperatures at poult arrival. Poults can lose a great deal of heat through their feet when they sit on litter that is cold and/ or damp. It is not uncommon to find floor temperatures several degrees lower than temperatures three feet above the floor. Therefore, make sure temperature sensors are near the floor at placement, not three to four feet above the floor.

Newberry (1993) reported that cool brooding of turkeys was associated with a faster litter moisture increase than warm brooding. Inadequate ventilation and high density rearing can also lead to a rapid increase in litter moisture in turkey houses. Litter moisture was shown to rise from a low level of 2% at time of placement to a high of 40% by four weeks of age (Anderson et al., 1964). Make sure that adequate ventilation rates are provided at placement and that these rates are increased as the flock ages to account for increased moisture removal requirements.

The effects of cool temperatures, poor ventilation and wet litter conditions are generally more harmful to young poults than to young broiler chicks. Brooding management which is less than optimal can decrease performance, increase feed conversion ratios and lead to conditions such as poult enteritis and mortality syndrome (PEMS). Poult enteritis and mortality syndrome has emerged as the most costly of the diseases affecting the production of turkeys (Edens et al., 1998). Afflicted poults suffer from severe diarrhea and dehydration, anorexia, weight loss and high rates of mortality when younger than six weeks of age (Barnes et al., 1996; Edens et al., 1997a,b; Qureshi et al., 1997). With the onset of PEMS, poults begin to huddle as if they are cold and crowd together to reduce body cooling. Litter moisture increases, presumably in association with severe diarrhea, and appears to be associated with increased severity of the disease (Edens et al., 1998). Adequate ventilation rates are vital to replenish oxygen; remove ammonia, carbon dioxide and moisture; and reduce levels of air-borne disease organisms. When good air quality is provided, poults will be more active and quickly seek out feed and water. High levels of carbon dioxide in houses have been shown to impair the poult’s ability to convert glycogen into glucose for energy (Wojcinski, N.D.). Therefore, in the presence of high carbon dioxide concentrations, poults may appear inactive, listless and disoriented and may lie on their sides paddling the air. Inadequate ventilation may also lead to spontaneous turkey cardiomyopathy (STC) or roundheart disease, a prevalent circulatory disturbance afflicting turkeys raised at moderate to high altitudes. Circulatory disturbances in turkeys are likely to become increasingly prevalent because of the economic need to continue to produce fast-growing strains of turkey (Frame et al., 1999).


Steps to Reduce Spontaneous Turkey Cardiomyopathy (STC)*

1. Ignite stoves at least 12 hours before poults arrive to be sure they are burning cleanly with a mainly blue flame and no smoke.

2. Make sure air is circulating within the brooder building. Mixing or circulation fans should be started at a very low speed soon after placement of the brood.

3.
Air exchange is just as critical as air movement. Poults should receive a minimum of 0.2 cubic feet per minute (cfm) of incoming air at placement.

4.
Poults should not be unnecessarily disturbed during the second and third weeks of life. In a flock with 2% mortality caused by STC, it is likely that 80 to 90% of the poults have some degree of heart damage so how the flock is handled, even after STC mortality starts, may have a dramatic impact on how many birds remain alive.

5.
Minimize the risk of turkeys becoming ill with poult enteritis. A risk study conducted in Utah turkeys indicated the risk of suffering significant STC loss was 21 times greater for a flock of hens brooded in winter with poult enteritis compared to a tom flock brooded in July with no poult enteritis.

6.
Keep poults from becoming chilled or overheated since both increase in metabolic rate and the demand for oxygen.

7. Light reduction programs through three weeks of age have shown beneficial results.

* From Frame et al. (1999)

While altitude is a definite predisposing factor, the time of year turkeys are raised also plays a significant role in STC development (Frame et al., 1999). Broods placed in winter have a higher incidence of STC than those placed in late spring or summer, possibly because of suboptimal air exchange during colder periods, since producers tend to skimp on ventilation time to save fuel. In underventilated houses, carbon dioxide builds up and oxygen availability lessens. A characteristic of STC mortality is that more turkeys die during the night than during the day. A possible explanation for this characteristic is that poults form microenvironments as they bed down and crowd together. Some of these microenvironments restrict air movement. If the ventilation is inadequate in the building, there is insufficient fresh air available, and birds succumb to the effects (Frame et al., 1999). Frame et al. (1999) indicated that various methods to reduce losses from STC have been identified, but some require very careful management by the grower.

Summary

More flock performance is lost due to improper brooding than from any other single cause. Management during the first two to three weeks after hatch has a dramatic impact on bird performance throughout the remainder of the flock. Performance lost during the brooding period can never be regained. To brood properly pay particular attention to building setup. Heat should be on several hours prior to bird arrival to allow the floor to warm and prevent birds from becoming chilled. Set brooders at the proper temperature for each flock. Ventilation and air exchange is critical to an optimum environment. Proper ventilation provides oxygen and removes carbon dioxide, ammonia, dust, disease organisms and humidity. Litter moisture can also be controlled through adequate ventilation. Maintaining optimum environmental conditions throughout the flock (and especially during the early brooding stage) coupled with a sound feed and water management program will help ensure production of a healthy, efficient and profitable flock.

References

Anderson, D.P., F.L. Cherms and R.P. Hanson. 1964. Studies on measuring the environment of turkeys raised in confinement. Poultry Sci. 43:305-318.

Barnes, H.J., J.S. Guy, T.P. Brown and F.W. Edens. 1996. Poult enteritis and mortality syndrome (“spiking mortality of turkeys”) and related disorders – An update and overview. Pages 1-11. College of Agriculture and Life Sciences, North Carolina State University, October 29, 1996, Raleigh, N.C.

Deaton, J.W., S.L. Branton, J.D. Simmons and B.D. Lott. 1996. The effect of brooding temperature on broiler performance. Poultry Sci. 75:1217-1220.

Dozier, W.A., and J. Donald. 2001. Keys to successful brooding. The Alabama Poultry Engineering and Economics Newsletter. No. 14, November. Alabama Cooperative Extension System, Auburn University, Auburn, Ala.

Edens, F.W., C.R. Parkhurst, M.A. Qureshi, G.B. Havenstein and I.A. Casas. 1997a. Escherichia coli strains and their association with poult enteritis and mortality syndrome. Poultry Sci. 76:952-960.

Edens, F.W., R.A. Qureshi, C.R. Parkhurst, M.A. Qureshi, G.B. Havenstein and I.A. Casas. 1997b. Characterization of Escherichia coli isolates associated with poult enteritis and mortality syndrome. Poultry Sci. 76:1665-1673.

Edens, F.W., K.A. Joyce, C.R. Parkhurst, G.B. Havenstein and M.A. Qureshi. 1998. Effect of litter moisture and brooding temperature on body weights of turkey poults experiencing poult enteritis and mortality syndrome. Poultry Sci. 77:411-415.

Frame, D.D., R.E. Buckner and G.L. Anderson. 1999. Causes and control of spontaneous cardiomyopathy or roundheart disease in Utah turkeys. Cooperative Extension Service, Utah State University, Logan, Utah.

Lacy, M.P. 1997. The effect of cool temperatures on broiler performance. Poultry Tips. January 1997. The University of Georgia College of Agricultural and Life Sciences, Cooperative Extension Service, University of Georgia, Athens.

Lacy, M.P. 2002. Broiler management. In: Bell, D.B. and W. D. Weaver, eds. Commercial Chicken Meat and Egg Production, 5th ed, pp 829-868.

Newberry, R.C. 1993. The role of temperature and litter type in the development of breast buttons in turkeys. Poultry Sci. 72:467-474.

Qureshi, M.A., F.W. Edens and G.B. Havenstein. 1997. Immune system dysfunction during exposure to poult enteritis and mortality syndrome. Poultry Sci. 76:564-569.

Vest, L.R. 1997. Environmental factors to consider when brooding chicks. Bulletin 855. The University of Georgia College of Agricultural and Life Sciences, Cooperative Extension Service, University of Georgia, Athens.

Wojcinski, H. No Date. Critical control points during brooding. Hybrid Turkeys, Kitchener, Ontario, Canada.

Author: G. Tom Tabler – AVIAN Advice (Volume 5, Number 1), University of Arkansas Cooperative Extension Service, Division of Agriculture, Poultry Science

Publication date: 09/01/2008 Technorati Tags:

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