Brooding is the most crucial, critical and decisive period in a breeder chick’s life. Especially the first two weeks. This period has a great impact on future performance of the flock. More than 50% is decided in this period as to how a flock performs for the rest of its life. Mistakes made during this period cannot be corrected later on. If this period is managed correctly, the genetic potential of the bird, in terms of hatching eggs, fertility, hatchability and maximum saleable day old chicks can be achieved.
This is an important period in which all systems of the chicken are in developing stage. The immune system is immature and unable to fight against diseases. The digestive system is undergoing enormous anatomical and physiological changes. The feathering system is not perfect. Thermoregulatory system (the system in which chick can regulate its body temperature) generally matures at 12 to 14 days under normal conditions. The chick is learning how to eat and drink. Unfortunately many farmers in Asian countries do not give proper attention to the brooding period. Later they face many difficulties in achieving good production, hatchability and good quality day old chicks, and then they cannot correct something that was not done properly in brooding.
Table 1 shows some salient points that are important for good and proper brooding.
|1. Bedding material|
|2. House preparation|
|3. Reception of the chicks|
|4. Monitoring & assessing conditions|
|6. Relative humidity|
|7. Use of the yolk|
In Asian countries rice hulls are generally used as bedding material. This material is not disinfected and is directly put into a clean brooding room which can bring many kinds of infections, especially E. coli. In Pakistan it was found in a trial that total count of E. coli was 6.0 x 103 CFU before treatment. The count was extremely low after treatment. Rice hulls should be treated before putting in brooding room. The author of this article has designed simple equipment through which it can be treated easily (see figure 1). The rice hulls goes through an auger while nozzles sprays disinfectant onto them. Dust should also be removed from the rice hulls by putting on a sieve and stirring. This will help to control dust in the brooding room which can cause many respiratory problems. Studies conducted in Canada using canola oil in litter to reduce dust found that lower dust levels reduced levels of ascites (Zuidhof, et al., 1997).House preparation
The house and all equipment should be disinfected, cleaned and set up well in time. All necessary items should be present prior the arrival of chicks. It is important to note that the heaters and brooders should be on well before the arrival of chicks. In winter 48 to 72 hours and in summer 24 to 48 hours is recommended. This will help in maintaining temperature of walls and especially the floors. The temperature of the floor is very important and it should not be less than 30 C, otherwise chicks will lose heat through their legs and they will lie down on floor and start losing more heat as most of the body portion is touching the ground. They will reduce their body temperature very rapidly and this will chill them.Reception of the chicks
Always handle gently the delicate baby chicks at your farm. Sterilize your hands or wear gloves before putting chicks from chick boxes to brooder room. Some farmers start counting chicks at delivery time, which takes a lot of time. This is not good practice because the chicks present in boxes will be dehydrated. Immediately remove all empty chick boxes and burn them. Allow only water for the first hour so that the chicks become familiar with water. Then spread feed on paper and in feeders. At the time of arrival of chicks give Vitamin C and glucose in water. It will provide instant energy to chicks. Make sure all the chicks have easy access to feed and water.Monitoring and assessing the conditions
It is important to monitor conditions in the brooder room. Observe the behavior, position, noise, and eating and feeding activities of chicks. When adequate house temperature is obtained and chicks are well managed, they should be distributed throughout the house and not huddling together or sitting mostly in the feed pans. To monitor accessibility to feed and water, take 100 chicks from different places and palpate their crops. The crops should be soft and full. A target is that after 8 hours of arrival of chicks, 80% and after 24 hours, 100% chicks should have full crops.Temperature
Proper temperature in the brooding room at chick level is important. Follow the company’s recommended temperature guidelines. As discussed earlier, the chick’s body thermoregulatory system is immature and the chick can reduce its body temperature from 40 C to 35 C within two hours after placement, if conditions are not optimal. Chilling puts lot of stress on chick. The chick will not eat, and if it does not eat, the yolk will not be absorbed; consequently the maternal antibodies will not be consumed. This can cause yolk infection, especially by E. coli. The septic yolk will increase mortality. With good management, first week mortality should not exceed 0.7%. Mortality is not the only problem because chilled chicks will not start as other chicks. They will have lower body weight and will cause uniformity problems. In the remaining period of breeder’s life, the flock will have less production average and many other complications may arise later on. Newly born chicks are very delicate and even 1 C less or more body temperature can create a great stress on them. It is very important that correct temperatures be maintained throughout the brooding period and especially first 15 days. Chilling and overheating are both lethal for chicks. Chilled chicks have very high incidences of “Ascities”. Continuous monitoring and vigilance is important during this period.Relative humidity (RH)
Relative humidity is also an important factor in brooding. Low RH can cause dehydration and high RH causes chilling and wet litter. Research have shown that in houses with whole house heating having nipple drinkers, the RH may be as low as 25% and where bell drinkers are used, the humidity may be 40% to 50%. In hatchers the RH is about 80% and if the chick is placed at 25% RH, it will feel a great shock. To prevent the chick from this shock the RH level in brooder house must be in between 70% to 75% for the first 3 days. As the chick grows, the requirement for RH decreases. When chicks are 18 days old the RH should be around 55 to 60%. There are many ways to balance this RH. The cheapest and easiest method the author of this article has experienced is to put some water in the duct attached with heater at every 15 meters distance. When hot air touches the water present in the duct, RH is increased and above targets in early days can easily be achieved. The only drawback is that vigilance is required. Whenever humidity is less add some more water.Figure 1: Rice hulls treatment equipment.The use of yolk sac
The newly hatched chick has some portion of the yolk located in the proximal portion of the small intestine. Nature has provided this for emergency nutrition for survival. Very importantly it contains the maternal antibodies, necessary for chick’s passive immunity. The yolk sac membrane directly absorbs the contents of the yolk sac. It can also be absorbed by yolk sac epithelium or by the intestinal mucosa. The yolk sac weighs about 8 gram and 25% of the yolk is lipids. The contents of the yolk sac are absorbed in 3 to 5 days under normal conditions.
In Asian countries management standards have been improved but still there are some misconceptions and wrong practices regarding the absorption of yolk.–
Some farmers do not offer any feed for 12 to 24 hours.–
Some farmers offer only ground maize for 24 or 48 hours.–
Some farmers force their chicks to run whole day and night and they assume that by this exercise the yolk will be absorbed soon.–
Some farmers keep their chicks in boxes for 5 to 6 hours and these boxes are kept in the brooder room and they consider this will help in absorption of yolk.
All the above practices are wrong and are dangerous for chicks. Recent research has shown that chicks require solid feed as soon as possible to stimulate the yolk absorption. Some international companies who dispatch their chick long distances have started putting some nutrition supplements in chick boxes. Delaying feed will delay the absorption of yolk and the initial growth will be suffered. Forcing chicks to run imposes stress and chicks cannot eat and drink; the result is a delay in absorption of yolk. Keeping the chicks in chick boxes in brooding room will definitely dehydrate the chicks and boost early mortality. Remember the yolk sac contains lipids and protein only whereas chick requires solid feed to promote the main changes in physical structure of the digestive system and its secretions, essential for the digestion of nutrients in this period. Immediate solid feed after hatch is required to stimulate the absorption of the yolk.Feed
As discussed above the digestive system of newly born chick is undergoing a lot of physiological and anatomical changes. Feed given during this period should be palatable, easily digestible, balanced and free of pathogens and toxins. Do not use ingredients that have higher levels of “Non Starch Polysaccharides” (NSP), for example wheat and rye etc. The NSP causes more viscosity in intestine and are responsible for poor digestion and wet litter. The texture of feed is also important. It should be appropriate for baby chicks enabling them to eat easily. Baby chicks cannot easily digest fats. Do not use fat sources such as tallow and lard etc.Water
Water is most important ingredient. It has important functions in chicken’s body. Generally a chick consumes water more than double that of feed. One of its functions is that it transports all nutrients in the body of chicken. If water is contaminated it will carry infection also in the body of chicken. Good quality clean water
free from microbes is required for best performance and better profitability (for details please see article ”The most important ingredient: Water”, published in Asian Poultry magazine, September 2007 issue.)Ventilation
Ventilation during the brooding period is also important. The objectives are:–
Good air quality–
Uniform shed temperature.–
Good litter conditions.–
Removal of moisture and noxious gases.–
Conservation of heat.
Oxygen is crucial to chicks for their survival. It is interesting to note that a young chick requires very little oxygen. Research has shown that the requirement of oxygen for a day old chick is only 0.00016 ft3 /min. Air is only 20% oxygen, so a chick needs 0.00083 ft 3/minute fresh air. Let’s say we had a 46 x 450 feet house with 25,000 day-old chicks, we simply multiply 0.00083 ft3/min x 25,000 chicks the result is only 21 cubic feet of fresh air per minute required. The oxygen consumed by heaters, brooders etc are about 3 times more than chick’s requirement. Two 36-inch fans will run only 1.2 second in five minutes to provide the necessary oxygen. To control these variables most experts agree that farmers should ventilate a minimum of 75 cfm/1000 chicks for first week, 150 and 300 cfm/1000 birds for second and third week respectively. These ventilation rates should be always for bird’s comfort and not for chick’s health and quality. The above stated ventilation rates are for reference only. These may be different in different conditions. It is always better to consult a ventilation expert. The air quality should be excellent in brooder house to get maximum performance. Levels of CO2 and ammonia should always be within acceptable range.Dr. Munawar Ali is General Manager of Islamabad Farms, Pakistan. He is responsible for broiler breeder management and poultry feed formulation and has 27 years practical experience.