Production of day-old chicks from crossbred chicken eggs by broody hens, rice husk incubator and electric incubator, and their rearing up to 6 weeks

B C Roy, H Ranvig*, S D Chowdhury**, M M Rashid and M R Faruque***

Department of Livestock Services, Krishi Khamar Sarak, Farmgate, Dhaka, Bangladesh
bibekroy@hotmail.com
*Department of Animal Science and Animal Health, The Royal Veterinary and Agricultural University, Copenhagen, Denmark
**Department of Poultry Science, Bangladesh Agricultural University, Bangladesh
***Chittagong Veterinary College, Chittagong, Bangladesh

Abstract

Nine hundred and sixty hatchable eggs were collected from the Parent flock of Rhode Island Red male and Fayoumi female, and set in three different methods of incubation. Each method was presented by four replications, and each replication consisted of eighty eggs. Twenty-four broody hens were used, and a rice husk incubator was constructed with locally available materials such as mat, jute cloth, bamboo, rice husk and wood. The eggs for all incubation processes were washed with savlon mixed luke warm water to remove dirt and surface organisms. During incubation period, turning of eggs was done manually in rice husk incubator, whereas electric incubator had an automatic turning device for once an hour, and broody hen was experienced enough herself. Candling was done in all processes. The hatching eggs were transferred from incubation box to hatching bed on 17^th day of incubation in rice husk incubator while the eggs were transferred from setting tray to hatching tray on 18^th day of incubation in electric incubator. Data were recorded for average egg weight, chick weight, fertility, embryonic mortality, dead-in-shell, abnormal chicks, normal chicks hatched, hatchability of fertile eggs and hatchability of total eggs set.

The results of this study indicated that egg weight, fertility, embryonic mortality, abnormal chicks, chick weight and normal chicks hatched did not differ significantly (P<0.05) among the treatments. Dead-in-shell, hatchability of fertile and hatchability of total eggs set showed significant differences (P<0.05) among the treatments. Higher dead-in-shell (5.5%) occurred in rice husk incubator followed by electric incubator (3.1%) and broody hens (2%). The highest hatchability (92.4%) of fertile eggs set was found in broody hens compared to electric incubator (89.3%) and rice husk incubator (87.5%). The chicks produced from three different methods of incubation were reared up to 42 days of age to investigate growth and survivability. During the rearing period, there were no treatment differences in body weight gain, feed consumption, and feed conversion.

Key words: broody hen, chick rearing, hatchability and rice husk incubator

Introduction

There are many ways of producing day-old chicks in Bangladesh. One is practiced by the broody hens under rural conditions, but the capacity of broody hens is not enough to meet the actual demand of farmers who want to carry out small-scale operations. A broody hen can hardly hatch 12 eggs. Surprisingly little is known about the efficiency of rice husk incubation. Modern electric incubators are equipped with automatic devices and generally used by the commercial hatcheries for hatching chicken eggs to meet the huge demand for quality chicks all over the world particularly in the developed countries.

Despite an increasing demand for quality chicks and ducklings, the hatchery operation in most of the developing countries is not well organized. Major constraints to this include shortage of electricity, irregular or intermittent electric supply, frequent power break-down, particularly in warm climates due to so-called load shedding, lack of stand-by generators to combat a situation arising from power failure, lack of adequate training of personnel and inadequate supply of day-old chicks from hatchery to rural area. This situation has received the attention of the poultry scientists and also of some non-governmental organizations of Bangladesh, who are working hard to improve the economic condition of the people through poultry rearing. Therefore, it has become necessary to find a method of incubation that is less risky and less expensive, but which could be adopted equally by all sections of urban and rural people through better utilization of existing resources in developing countries like Bangladesh.

Abundant literature is available on the hatching performance of eggs of domesticated fowl under artificial incubation, but only little work has been performed on domesticated fowl under rural conditions. A comparative study on the hatchability traits of crossbred chicken eggs by the use of broody hens, rice husk incubator and electric incubator, has not yet been done. Information on growth and survivability of chicks hatched out from those systems of incubation is scanty. So the current study is aimed at the following objectives; to study the hatchability traits (fertility, hatchability, and dead-in-shell, embryonic mortality, normal and abnormal chicks) of eggs from crossbred (RIR x Fayoumi) chickens by using broody hens, rice husk incubator and electric incubator and to investigate growth and survivability of chicks hatched by broody hens, rice husk incubator and electric incubator.

Materials and methods

The experiment was carried out with 960 eggs collected from the parent flock of RIR male and Fayoumi female, and set in three incubation methods: natural incubation, rice husk incubation and electric incubation with 4 replications of each individual method. The experiment was started on 8^th November and continued up to 24^th January 2003 at Mithapukur area of Rangpur, Bangladesh. At every five days, 80 eggs were set in each system at the same time, 2 p.m. Incubation house, nest for broody hens, rice husk incubator and chick rearing units were constructed in the research area, and the Government poultry hatchery of Rangpur, Bangladesh, was used for electric incubation. The experiment was divided into two phases. First phase was incubation, and second phase was rearing of day-old chicks up to 42 days of age.

Care of hatching eggs

The hatching eggs were medium and uniform in size and had strong shells. Special care was taken to exclude cracked or very dirty eggs from this study. The eggs were kept in collecting trays, keeping the blunt end up, and stored in a room at 14⁰C to 16⁰C and 70-80% relative humidity, over a period of 4 days. Before setting, all eggs were properly cleaned with mild luke-warm water solution of savlon (a mild disinfectant). Shape index of hatchable eggs was measured.

Experimental Phase-1

Natural incubation (by broody hens)

Selection and collection of broody hens

As hens sit to hatch when they become broody, they are not always at hand to hatch eggs regularly. Special attention was given to selection of broody hens. When an indigenous local hen displayed typical broody sound, occupied her nest, refused to leave it and tried to gather eggs, and this behaviour lasted at least two days, then it was assumed that the hen was ready for brooding. The weight ranges of broody hens were from 960 g to 1300 g. Twenty-four broody hens were collected from neighbouring villages of the research area. These twenty-four broody hens were used for 4 replications. Each replication needed 6 broody hens for incubation of eighty hatching eggs. Two weeks before the collection of broody hens for incubating eggs, special attention was paid to the laying period of each broody hen. When a hen laid six eggs, then it was collected and put in the predetermined incubation house for acquainting her with stipulated incubation boxes.

Preparing for hatching and care during brooding

Before setting, all broody hens were treated with two drops of Ivomac on the skin in the neck region to remove both internal and external parasites. After treatment with insecticide against parasites, the hens were put in a clean nest box. At first, until the hen had 7 to 12 eggs, it sat irregularly. Once when the hen started sitting after laying 16-17 eggs, then all eggs were removed and replaced with selected hatching eggs. Maximum16 eggs were placed under a big hen (1300 g), while 10 eggs were placed under a small size hen (960 g). The total weights of incubated eggs were almost half of the body weight of broody hens. Before and after setting of each replication, all broody hens were weighed individually. Although a compound (pelleted) layer grower ration containing 12.9 MJ/kg and 16.4% CP, fresh drinking water and dust bath were provided for the broody hens in the incubation house, even then the broody hens left their nest at least once a day and stayed outside about 15 to 20 minutes. A water container was kept in the incubation house to maintain proper humidity. The eggs were candled by torchlight on the 7^th and 14^th day of incubation. All clear and early dead embryos were removed after candling.

Rice husk incubation

Drying, marking, making bundles and heating of eggs

The hatching eggs were dried in the air, and after drying all eggs were marked with different symbols for identification of each batch. The hatching eggs were tied up in bundles of 20 in each group. Red cloth was used for bundles. For heating, the bundles were opened and placed on mats exposed to sunlight. A thermometer was inserted in a cracked egg. When the temperature was about 39^oC, the eggs were tied up in bundles again. All the pillows of the rice husk incubator were warmed by solar energy up to 39^oC simultaneously.

Placing the pillow and egg bundles in the incubation cylinder

A warm pillow was placed at the bottom of the cylinder. Then the warmed up bundles were placed on this pillow. After placing the egg bundles, another warm pillow was placed over the bundles. This created a sandwich of eggs between two heated pillows. All eggs were kept to remain in this way for 24 hours without any further attention.

Turning of eggs

After 24 hours, the eggs were taken out from incubation cylinders and turned. Turning was done by placing the bundles on a winnowing tray over the turning cylinder. The bundles were opened, and the eggs were spread out. The eggs were then rolled with a gentle circular motion of hands. The bundles were retied and replaced in another cylinder so that the bundle that was formerly on the top was then at the bottom and vice-versa. When the temperature was found to be 37^oC to 38^oC, the eggs were not reheated, only the pillows were reheated. The eggs were reheated when the temperature was found to be below 37^oC. All eggs were turned. Turning of eggs was done 6 times in 24 hours at 4 hours interval up to 16 days of incubation. From the 17^th day until piping all eggs were turned 12 times in 24 hours at 2 hours intervals.

Candling of eggs

For candling the eggs, the incubation room was darkened. Torchlight was used for this purpose. The eggs were held up in front of the torch so that the inside was visible. The fertile eggs showed a small dark spot that looked something like a "spider". Infertile eggs were clean and only showed the shadow of the yolk. After candling, eggs of a new batch with different marking were mixed with old eggs. Before being mixed, the new eggs were heated to adjust the temperature with the older ones. The eggs were candled on the 5^th, 10^th and 15^th day of incubation.

Transfer of eggs from incubation cylinders to hatching bed

On the 17^th day of incubation, the eggs were transferred to hatching bed. The eggs were laid on their sides in one layer and were packed very closely in the bed. When the whole surface was not covered, a rolled jute cloth was placed across the open edge to hold the eggs tight and to conserve heat. In the hatching bed, the eggs were covered with a light jute cloth. When the egg temperature was found to be above 39^oC, no cover was used.

Humidity

To maintain proper humidity a container of water was always kept in the incubation house. On the day of hatching, a pot of hot water was placed in the hatching bed for 5 minutes at one-hour intervals so that its vapor maintained proper humidity. A white cotton cloth rinsed in luke-warm water was spread over the eggs for a period of 3 minutes at one hour intervals by removing its excess water. This system was applied only on the day of hatching and only when the humidity was below 90%.

Temperature

A clinical thermometer was inserted into the egg bundles at different levels to check the temperature. From 12 days of incubation the embryos were large enough to keep up the temperature without assistance. The uppermost pillows of incubation cylinders were not necessary from 13 days of incubation. In case of sudden change in weather leading to coldness, the pillows were again used for the maintenance of proper temperature.

Taking off hatch

From the 19^th days of incubation, the chicks inside the eggs started piping. They were hatched with no assistance from anyone, about 24 hours after they first cracked their shells. Each hatch was taken off on the 21^st day of incubation. All the shells and dead in shells were removed immediately on completion of each batch.

Electric incubation

Before setting the eggs, the incubator was properly cleaned and disinfected. Before and after setting of eggs, the incubator was thoroughly fumigated by using potassium permanganate and formaldehyde as per recommendations. The eggs were set in the setting trays of the incubator with the small end down and the large end up. The optimum conditions of temperature, relative humidity and ventilation were maintained during the whole period of incubation as per recommendation of the manufacturer of the incubator. The automatic turning device was also used in the incubator as per recommendation. Candling was done by an electric candler on the 7^th and 14^th day of incubation to determine the fertility and early embryonic mortality of hatching eggs. The discarded eggs were broken and examined macroscopically. The hatching eggs were transferred from the setting trays to the hatching trays on the 18^th day of incubation. After each hatch, the unhatched eggs and pips were also broken for determination of dead-in-shells.

Data collection

Fertility, embryonic mortality, dead-in-shells, abnormal chicks hatched, normal chicks hatched, day-old chick weight, hatchability of total eggs set and hatchability of fertile eggs set were calculated in all methods. All hatched chicks were weighed individually on a treatment basis with 0.5 g accuracy.

Experimental phase-2

Rearing of chicks up to 42 days of age

After each hatch, sixty chicks of each batch were immediately transferred to chick rearing units and distributed in three predetermined pens. Each pen was used for the chicks of an individual method. The same procedure was followed for the remaining three batches. Chicks of all pens were brooded under a brooder. Electric bulbs were used in the brooder to provide sufficient temperature. For the first three days, newspapers were used as litter material. Number, height and strength (watts) of the bulbs in the brooder regulated the temperature. After 3 days fresh, dried rice husk was used as litter at a depth of about 0.04 m.

The birds were exposed to continuous lighting of 24 hours on the first 3 days. Then light was reduced by one hour at the end of every week. During the night, electric bulbs were used to provide the necessary light. One round tube feeder was used for 10 chicks, and one tube drinker was provided for 50 chicks. The feeders and drinkers were fixed in such a way that the birds were able to consume feed and drink water conveniently. Cleaning of feeders was done at the end of each week and water pots were washed daily. The floor space allowed for each bird was 0.093 m² up to 42 days of rearing. A layer starter pellet ration was supplied ad libitum to the birds throughout the experimental period. All chicks were vaccinated against Infectious Bronchitis, Infectious Bursal Disease and Newcastle Disease as per manufacturer's recommendations. Proper hygienic and strict sanitary measures were also taken during the experimental period. Initial body weight, weekly body weight, weekly feed intake and daily mortality were recorded throughout the experimental period.

Statistical analysis

Descriptive analysis was performed using mean and standard deviation for each outcome variable. Differences between treatments were evaluated using analysis of variance (Proc GLM in SAS version 8.2). When treatments were significantly different, the Duncan Multiple Range Test (1955) was used to separate treatment means (Steel and Torrie 1980). Assumptions for the analysis were evaluated using residuals plots and Shapiro-Wilks test for normality. A 5% significant level was used.

Results

Weight of hatching eggs, fertility and embryonic mortality of three different methods of incubation showed non-significant differences (Table 2).

The percent of dead-in-shell differed significantly among the treatments. Abnormal chicks, normal chicks hatched, chick weight as percent of egg weight were obtained with non- significant differences among the treatments. Table 2 clearly shows that the hatchability of fertile and total eggs set differed (P<0.05) among the treatments. Hatchability of fertile eggs was the highest in broody hens, intermediate in electric incubator and the lowest in rice husk incubator. Chick weight at hatching did not show any significant differences among the treatments. All variables recorded during the rearing period of crossbred chicks showed non-significant differences among the treatments (Table 3).

Discussion

The weights of the hatching eggs in the 3 different treatments were 42.2 g, 42.8 g and 42.3 g, respectively in this study. There was no significant difference. It might be due to the fact that all hatching eggs were collected from same parent flock which was sound and produced uniform eggs. The average fertility observed in the three different treatments was 90.6, 90.9 and 90.9 %, respectively.

The highest embryonic mortality occurred in electric incubator (5.5%) followed by those of broody hens (4.8%) and rice husk incubator (4.8%). The types of incubation had non-significant effect on the percentage of embryonic mortality. Such a results agree with those of  Khalil (1960) who stated that embryonic mortality rates in the eggs of Fayoumi chicken were 6.1%, 2.7% and 14% during 3 weeks of incubation. In a study of hatchability of chicken eggs, Dev et al (1993) reported 17.1, and 4.6% embryonic mortality in rice husk incubator and electric incubator, respectively.

The highest percentage of dead-in-shell was recorded in rice husk incubator (5.5%) followed by electric incubator (3.1%) and broody hens (2%). The higher percentage of dead-in-shell in the rice husk incubator might be due to lack of optimum conditions of temperature and relative humidity during the incubation period. After 12 days of incubation when chicken embryos mature rapidly, they produce enough heat due to metabolism. To maintain this temperature both in the incubation box and hatching bed is very difficult. Lack of  special care may cause a severe increase in the proportion of dead-in-shell. Broody hens are experienced enough to maintain optimum conditions of temperature and humidity,  whereas the electric incubator is well equipped to maintain optimum conditions. Dev et al (1993) reported that dead-in-shell rates in the rice husk incubator and electric incubator were 20.4 and 10.1%, respectively. El-Ayadi (1956) reported that dead-in-shell rates were almost equal in Baladi and White Leghorn eggs (19% and 20.0%, respectively).

There were no differences in the incidence of abnormal chicks among the treatments. Abnormal chicks are produced due to poor management of the parent flock as well as poor environmental conditions in the incubator and some genetical factors. The implication from the findings of the present study is that the methods of incubation had no effect on abnormal chicks hatched. The treatments also had  no influence on normal chicks hatched. Number of sound chicks is an indication of success of hatchability. The percentages of normal chicks in the present study were 98.9, 99.6 and 97.9% in broody hen, rice husk incubator and electric incubator, respectively. This finding is supported by the results of Dev et al (1993). They found 97.4 and 90.1% normal chicks from electric and rice husk incubator, respectively.

The highest percentage of hatchability was recorded in broody hens (92.4%) followed by electric incubator (89.3%) and by rice husk incubator (87.9%). The high value for broody hens in the present study is supported by the reports from Wilson (1979), Minga et al (1989) and Gunaratne et al (1993).

Conclusions

• Broody hens were more efficient then rice husk or electric incubators in producing day-old chicks. However, differences in hatchability were relatively small  indicating that the rice husk method could be used in remote areas where there is a high demand for day-old chicks, cheap labour, lack of electricity and inadequate facilities to transfer day-old chicks from commercial hatcheries to chick rearing units.
• Different incubation methods appear to have no influence on growth and survivability of day-old chicks.
   

Acknowledgement

The Danish International Development Agency (DANIDA) funded this research project. The authors appreciate the provision of funding.
 

References

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El-Ayadi M N 1956 Fertility and hatchability as related to quality in Baladi commercial eggs. M.Sc. Thesis, University of Alexandria, U.A.R. Cited from, Poultry Science, 41(2): 1707-1712.

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