Livestock Research for Rural Development 23 (9) 2011 Notes to Authors LRRD Newsletter

Citation of this paper

Evaluation of options for improving hatchability in indigenous free-range chickens in Eastern Uganda

H Kirunda and N Muwereza*

* National Livestock Resources Research Institute (NaLIRRI),
PO Box 96, Tororo, Uganda
halidkirunda@gmail.com

Abstract

Different options for improving hatchability in indigenous free-range chickens were evaluated. The aim was to establish alternatives that could increase mean hatchability to more than 80% as previously reported in village chickens in other countries. A total of 1,182 hens were recruited. Farmers were required to provide water and feed provision at nest, turn eggs in the nest and monitor hens for any mite infestation. Independent variables were site of egg storage, type of nest material, number of eggs provided to hen to incubate and hen-cockerel relationship. The study response variable was hatchability proportions. Data on these parameters were captured. Quantitative data were analyzed by SPSS for descriptive statistics and determination of significance of relationships done using Kruskal-Wallis Test (p=0.05).

 

There was a significant relationship (p<0.05) between hatchability and site of egg storage; nest material used; number of eggs incubated; and the relationship between parent hen and cock.  Hens incubating egg stored on trays, using cotton as nest material, incubating 12-14 eggs and mated to unrelated cockerel had frequencies of  >80% mean hatchability in at least 55.0%, 57.9%, 58.5% and 57.3% of the study hens, respectively. In addition to provision of water and feed at nest and turning eggs at least four times a day, farmers should be encouraged to use egg trays for storage, use of cotton, straw or sawdust as nest material, provide only 12-14 eggs and mate hens only to unrelated cocks if hatchability is to be increased to> 80% among free-range chickens in Eastern Uganda.

Key words: Egg site storage, feed and water supplement, nest material, number of incubated eggs


Introduction

In Uganda hatchability among free-range chickens had been reported to range from 70.8% and 85.7% (Illango et al 1999) and 45-75% (Byarugaba et al 2002). Whereas hatchability of 80% (of eggs set) from natural incubation is normal or a range of 75 to 80% is considered satisfactory (Sonaiya and Swan 2004) higher hatchability proportions had also been reported among village chickens in other studies in other countries (Wilson 1979; Kusina et al 1999; Moges et al 2010). A mean hatchability in the range of 80.4% in dry season to 89.3% in the wet had equally been observed in a more recent study in Eastern Uganda (Kirunda et al 2010).  

Several factors have been reported to affect hatchability of eggs and, among others, they include season of lay, disease, nutrition, chicken age, egg quality, genetic factors, hygiene and incubation conditions in the nests, (Horst 1988; Austic, et al 1990; Sainsbury 1992; Ojok 1993; Walsh et al 1995; Kabilika et al 1999; Danilov 2000; Kirunda et al 2010). Incubation conditions mainly include temperature, humidity, ventilation, position, and turning of the eggs (Wilson 2004; Tona et al 2003). It is required that eggs are turned at least 3-6 times daily during the incubation period (http://www.sabong.net.ph/forum/) in order to enhance higher hatchability proportions. Proportion of up to 72.9% was achieved when eggs were turned at least thrice a day (Abiola et al 2008). In addition, eggs initially need a very controlled heat input to maintain the optimum temperature of about 38C and  moisture levels of 60 to 80% of relative humidity for appropriate embryonic development (Sonaiya and Swan 2004). To ensure that appropriate warmth is maintained under natural incubation, straw, rice hulls and sawdust (Shahvali et al 2000) are among the nest materials that have been tried. Under natural incubation, an optimum number of eggs should be given to a hen. While up to 20 eggs have at times been given to hens to incubate (Shahvali et al 2000), a maximum of 14 to 16 eggs may be brooded in one nest because hatchability has often been observed to decline with more than ten eggs (Sonaiya and Swan 2004).  

This study was undertaken to evaluate options for improving hatchability in indigenous chickens in Eastern Uganda. It was conducted based on findings of an earlier study (Kirunda et al 2010), which revealed a significant variation in hatchability among hens incubating on different nest materials in the region.  


Methods and Materials

Study area  

Study area included sub-counties in the banana-coffee and banana-millet-cotton farming systems - agro-ecological zones in Uganda (Mwebaze 2006). The districts of Iganga and Kamuli were purposively selected because they are among the areas with the highest density of local chickens in Uganda (UBOS/ILRI 2002). The sub-counties of Irongo, Nawandala and Nabitende in Iganga district and Namwendwa and Nawanyago of Kamuli district were selected. A total of eight villages; four in Iganga and four in Kamuli were used, with each participating in the evaluation of the four study parameters.  

Sample size 

Since the study was a single-group experiment for continuous variable, sample size was determined using the equation described by Snedecor and Cochran (1989);

where s = the estimated population standard deviation of hatchability of 15 - based on the mean hatchability of Uganda of 60% (45% - 75%) reported in a recent study by Byarugaba et al (2002) and d = the difference between 75% (Byarugaba et al 2002) and 77% mean hatchability regarded satisfactory under natural incubation (Sonaiya and Swan 2004). Substituting 15 for s and 2 for d, and computing for n, sample size of 1182 was adopted and therefore was 1182 hens recruited for the study.  

Study design  

Hens previously vaccinated against Newcastle disease were recruited from households where laying hens were found and in which farmers were ready to provide at least one of the nest materials under study. Laying hens were recruited and farmers in the study households asked to collect the laid egg from each of the nests of the selected hen. Egg collection was done on a daily basis and eggs of a given hen stored in specified site. For ease of determination of the date on which an egg was laid, eggs of each hen were individually labeled before being stored. Storage sites included: on the floor, on cotton wool, inside box/basket, on sand or ash, on coffee husks, on egg trays in pots, on sawdust. As another storage site farmers were asked to just leave eggs on the nest. No temperature recording or monitoring was done for any of the study storage sites. When a hen appeared to have stopped accumulated eggs were after selection given to the hen to incubate. Eggs were selected starting with the egg laid last in the clutch, that is, in a reverse order. The incubated eggs were therefore aged day 1 to a maximum of 15 days. Hens were grouped into four categories depending on the nest materials used in the nest. One of four different types of materials was used for each incubating hen. The material included cotton, ash, sand and straw/sawdust. Each hen was provided with 10, 11, 12, 13, 14 or 15 eggs to brood, but no temperature recordings were taken for any of the nest materials used. Each farmer was asked to ensure that the brooding hen was provided with water and feed supplements (Sonaiya and Swan 2004) at the nest and its eggs turned four times each day for at least 18 days. Mites were controlled in the study households. Records about the relationship between each recruited hen and its mating cock were taken. 

Data collection and analysis

 

A record card was used to capture data on the different study parameters. Parameters (independent variables) included egg storage site, nest material used, number of eggs provided for incubation and the relationship between the hen and cock. The other parameter (dependent variable) on which data was captured was number of eggs hatched, from which the hatchability percentages per hen were computed. Quantitative data were entered into and analysis made using Statistical Program for Social Scientists (SPSS) version 12.0 for Windows. Analysis was done by descriptive statistics and determination of significance of relationships for response variables made using a non-parametric test for independent samples, Kruskal-Wallis Test (p=0.05). The data were also imported into and figures drawn by Microsoft Excel program. 


Results

Effect of site of egg storage on hatchability 

Results of evaluation of options of sites of egg storage are shown in Table 1. The study observed that there was a significant effect (p<0.05) between the site of storage and the proportion of egg hatched by hens on free-range management system. Out of the 218 that incubated eggs previously stored on egg trays, up to 96.8% of them had beyond 80% hatchability. This was followed by hens that incubated eggs stored on cotton wool (88.6%, n=88), in a pot (84.8%, n=46), on the floor (68.4%, n=19), in a box/basket (61.3%, n=119), left on the nest (44.5%, n=501) and stored on sawdust (42.9%, n=14). Among the study hens that achieved >80% hatchability only 4.3% (n=114) and 3.1% (n=63), respectively, incubated eggs previously stored on sand/ash and on coffee husks.


Table 1. Percentage of hatchability by site of egg storage

Storage site

Number of incubating hens

Percentage of hens with >80% hatchability

On the floor

19

68.4%

On cotton wool

88

88.6%

Inside a box/basket

119

61.3%

Leave eggs on nest

501

44.5%

On sand/ash

114

4.4%

On coffee husks

63

3.2%

On egg trays

218

96.8%

In a pot

46

84.8%

On saw dust

14

42.9%

Effect of nest materials on hatchability 

Material used on the nest caused variation in hatchability with results revealing significant effect (p<0.05) between nest material used in the nest and the percent hatchability achieved per study hen. Among the four materials evaluated, the highest hatchability percentage was achieved with cotton. Of the 311 hens that incubated on cotton, 242 (77.8%) of them had their hatchability surpass 80%. This was followed by hens that incubated on ash (55.5%, n=292) and sawdust/straw (52.5%, n=284). Only 44.4% (n=295) of hens that incubated on sand exceeded 80% level of hatchability. The hatchability proportions of hens based on types of nest materials are shown in Fig.1. Deducing from the trend shown in the results, the performance of ash was not consistent.   


Figure 1. Numbers of hens achieving hatchability (%) ranges with different nest materials
Effect of number of eggs incubated on hatchability 

Effect of number of eggs incubated and hatchability levels were statistically significant (p<0.05) among the study hens. Table 2 presents the frequency and percentages of hens that achieved hatchability proportions exceeding 80% with the different numbers of eggs incubated during the study period. Up to 216 hens (91.5%) of the 236 hens that incubated 13 eggs achieved hatchability proportions of >80%. Additionally, as many as 223 (84.8%) and 126 (62.1%) of hens that incubated 12 and 14 eggs, respectively, equally achieved hatchability rates beyond 80% while 58.5% (n=120) and 45.5% (45.5%) among those that incubated 11 and 10 eggs managed to achieve this level of hatchability.


Table 2. Percentage of hatchability by site of egg storage

Number eggs incubated

Frequency

Number of hens achieving >81% hatchability

Percentage

10 eggs

204

93

45.5%

11 eggs

204

120

58.5%

12 eggs

263

223

84.8%

13 eggs

236

216

91.5%

14 eggs

203

126

62.1%

15 eggs

72

18

25.0%

The smallest proportion (25.0%, n=72) of hens to get >80% hatchability were those which sat on 15 eggs. Regardless of the number of eggs incubated, the lowest hatchability proportional range recorded was 41-50%, which was exhibited by only 0.05% of the 1,182 study hens (results not shown) and this was mainly among hens that incubated on ash.  

Effect of parental relationship on hatchability 

Numerical variation in hatchability was observed among hens that laid and incubated eggs having been mated to cocks with which such hens shared some genetic relationships. The effect of hen-cock (parents) relationship on hatchability was significant (p<0.05). Hatchability proportions beyond 80% were mostly (66.1%, n=917) achieved among hens that did not have any form of genetic relationship with their mating cocks (Table 3).


Table 3. Percentage of hens that achieved >80% hatchability  based on effect of parental relationship between cock and hen

Relationship

Frequency

Percentage of hens with >80% hatchability

Cock is father to hen

42

16.7%

Cock is grandfather to hen

50

16.0%

Cock is son to hen

72

43.1%

Cock is grandson to hen

61

20.0%

Cock is brother to hen

40

27.9%

No relationship to hen

917

66.1%


Smaller proportions of hens that had relationships with their mating cocks achieved hatchability percentage of more than 80%. Among hens that were mated to cocks with which they had a breeding relationship, the biggest proportion of hens to achieve >80% hatchability was among hens that were mated with cocks which were sons. The proportion among this group that achieved hatchability of the study target only 43.1%. This was followed by only 27.9% and 20.0% of hens were mated to brother and grandson-related cocks, respectively. Hens bred to cocks that had a father or grandfather relationship had the lowest proportion of hens to achieve hatchability percentage exceeding 80% and the respective proportions of such hen categories were only 16.7% and 16.0%.        


Discussion

In this study the hatchability proportions ranged from 45 - 100%, with mean hatchability of 81.5%. Regardless of the parameter of study, at least 57.3% out of the 1,182 hens achieved hatchability proportions that exceeded 80%. The range of hatchability reported in this study is similar to 50-100% reported in United Republic of Tanzania (Minga et al 1989), 60-90% in Burkina Faso (Bourzat and Saunders 1990) and 60-95% in Senegal (Gueye 2003). While the study hatchability range was higher than 70.8-85.7% (Illango et al 1999) and 45-75% (Byarugaba et al 2002) reported in earlier studies in Uganda and 70.1-78.3% in Nigeria (Sola-Oja 2011), it was lower than 70-100% reported in other studies (Fayeye et al 2005; Alaba 1990; Atteh 1990). Mean hatchability of this study was higher than 80.9% (Tadelle and Ogle 1996) in Ethiopia; 69.7% (Eugene 2004) in Philippines, 78% (Khalafalla 2000) in Sudan and Nharira (69%) and Lancashire (74%) in Zimbabwe (Maphosa et al 2004) despite the fact that it was lower than  90% hatchability of village chickens in Sudan (Wilson 1979), 82% in communal area of Zambabwe (Kusina et al 2000), 81.7% in Ethiopia (Moges et al 2010) and 84.9% hatchability reported in a study in Uganda (Kirunda et al 2010). The probable reasons for lower mean hatchability resulting from this study are, among other, the longer time storage of eggs and possible bacterial contamination from the storage sites and nest materials that were locally solicited and non-sterilized. In our study most of the eggs were stored beyond four days with some of them being stored for up to 15 days. Storage for only four days (Decuypere and Michels 1992; Schmidt et al 2009) is most recommended, although under natural incubation egg storage may be extended to maximum of 14 days (Elibol and Brake 2008). Contamination of eggs by bacteria from the environment has been reported in several countries (Kibikika et al 1999; Siddiqui et al 2008; Nemati et al 2008) including Uganda (Kirunda et al 2010).  

Whereas tray egg storage resulted in higher hatchability proportions, proportionately lower hatchability was with other storage sites. The variation in hatchability proportions could easily be attributed to site of egg storage. The storage site effect could be strengthened by the fact that all eggs used in the study were from hens vaccinated against Newcastle disease (the most prevalent disease) and were selected against cracks, infertility, shape deformity, improper shell thickness and for inappropriate size. Since the egg and host factors that affect hatchability had been minimized, it is mainly the storage site factors that could therefore have significant influence on hatchability. Several factor such as site temperature, humidity and hygiene affect hatchability (Austic et al 1990; Sainsbury 1992; Brake et al 1997; Kabilika et al 1999; Danilov R V 2000; Ruiz and Lunam 2002; Samli et al 2005). 

In this study a significant deviation in percent hatchability was observed with sand and coffee husks. Whereas storage in sand has occasionally been recommended (Olsen and Clubb 1997), in this study on-sand egg storage was investigated. Therefore, sand surface temperature, appears to have had a greater influence than the temperature inside the sand bed. Sand has been described to be a good heat absorber. It can be warm in the day though may be cooler at night (Weeks 2003); sand particles exposed to heat will get pretty warm or hot, pretty fast. Although sand gets much cooler a few centimetres down, the surface of the same sand can concomitantly be warm (Week 2003). Since dry sand is known to be poor at heat transfer, it is possible that sand maintains warmth on its surface for longer hour into the night and hence subjecting the eggs to warm temperatures for longer hours. Sand surface temperature, just as the temperature on the surface of the coffee husks could greatly be influenced by the environmental and room temperature in houses of egg storage. In Uganda, environmental temperature range is 25oC-30oC while the average room temperature during day time is 25oC and relative humidity of 70-100% (Nshemereirwe 2004; PATH 2010). Night temperature, in the study area may however frequently be cooler (about 18oC). Whereas Uganda’s room temperature is within the normal range of the physiological zero (27oC) - the temperature that must not be exceeded during egg storage (Walsh et al 1995) - for increased hatchability, eggs should optimally be stored at 12.7C and 65-85% relative humidity (Parker and Parker 1969; Anderson 1979) or 12.8-18.3C and 75% relative humidity (Walsh et al 1995; Olsen and Clubb 1997) in a clean egg tray or in sterilized sand. Since literature on use of coffee husks as a storage material is largely lacking discussion of effect of sand could not be readily discussed. The possible bacterial contamination, which could have occurred to eggs stored on sand and coffee husks may partly be used to explain the lower hatchability since these two materials were not sterilized when used in this study.  

A significant relationship between the nest materials used and hatchability was observed. This could be attributed to the difference in the ability of different materials to maintain warmth. Whereas some materials used by farmers of Eastern Uganda are good at maintaining warmth, others could be relatively poor. The good hatchability proportion reported of cotton, straw and sawdust in this study could be due to the ability of these materials to maintain warm and the reason for promotion of their use by farmers in some countries (Shahvali et al 2000). Much as hens incubating from ash showed fair proportions of hatchability, its trend in influencing this was not clear. Since no literature was readily available on the use of ash as a nest material, the effect of ash on hatchability could not be adequately discussed.  

The best hatchability proportions were shown by hens that incubated 12-14 eggs and the worst rates were among hens that sat on 15 eggs. This was consistent with a study by Moges et al (2010) in which hatchability proportion of 84 – 86% was reported among hens that incubated 13-14 eggs in Ethiopia and Sonaiya and Swan (2004) who indicated that a maximum of 14 to 16 eggs could be brooded in one nest. Results of our study continued to confirm that hatchability often declines with more than ten eggs (Sonaiya and Swan 2004). The size of hens in the two farming systems of study is about 1.5 kg live weight, which is of medium size among indigenous hens in Uganda (Ssewannyana et al 2003). Such hens can easily sit and cover between 12 and 14 medium size eggs (50-55g) (Sonaiya and Swan 2004) but may not be able to do so with eggs beyond that number.  
 

Variation in hatchability among hens that laid and incubated eggs having been mated to cocks with which such hens shared some genetic relationships was observed in our study. This could be attributed to genetic factors. Like revealed decades ago (John and Merritt 1955; Washburn 1990) and in recent years (Szwaczkowski et al 2003), our study equally observed lower hatchability proportions among hens that were mated to closely related cocks. The closer the relationship the lower the hatchability, the study was revealed. 


Conclusion and recommendations


Acknowledgements

We are grateful to farmers and staff of veterinary department and NAADS Programme in Iganga and Kamuli districts.  Thanks are also extended to National Agricultural Research Organisation (NARO) for Project Coordination, and Government of Uganda and World Bank for funding the study. 


References

Abiola S S, Afolabi A O and Dosunmu O J 2008 Hatchability of chicken eggs as influenced by turning frequency in hurricane lantern incubator. African Journal of Biotechnology 7 (23):4310-4313.

 

Alaba A O 1990 Fertility and Hatchability of eggs from cross breeding Dahlem Red and Local chicken. B. Agric Project, OAU, Ile-Ife, pp. 40-65.

 

Anderson A F 1979 The Incubation Book. Brown Saiga Publishing Co. Ltd., Hindhead, Surrey, England http://wildlife1.wildlifeinformation.org/S/00Ref/BooksContents/b106.htm, Last Accessed April 2011.

 

Atteh J O 1990 Rural poultry production in Western Middle belt region of Nigeria, In proceedings of international workshop of rural poultry in Africa Edited by Sonaiya E B), November 13-16 1989, Ile-Ife, Nigeria, pp. 211-220.

 

Austic R E, Malden C and Nesheim 1990 Factors in hatchability. In Poultry Production 13th Edition, Lea and Febiger, Philadephia USA pp. 112-115.

 

Bourzat D and Saunders M  1990  Improvement of traditional methods of poultry production in Burkina Faso. In Proc CTA seminar, 3rd International Symposium on poultry production in hot climates, Hameln, Germany, 12 June 1987.

 

Brake J, Walsh C, Benton J R, Petitte N J, Meijerhof R and Penalva G 1997 Egg handling and storage. Poultry Science 76:144-151.

 

Byarugaba D K, Olsen J E and Katunguka-Rwakishaya E 2002 Production, Management and Marketing Dynamics of the Rural Scavenging Poultry in Uganda. Second FAO/INFPD Electronic Conference on Family Poultry 2002 on Bangladesh Model (http://www.fao.org/WAICENT/FAOINFO/AGRICULT/AGA/AGAP/LPA/FAMPO1/Famp).

 

Danilov R V 2000 Effect of hen’s age on quality of hatching eggs and embryonic development. Proceeding of 21st World’s Poultry Congress, 2000, Montreal, Canada.

 

Decuypere K and Michels H 1992 Incubation temperature as a management tool: a review. World’s Poultry Science Journal 48: 27-38.

 

Elibol O and Brake J 2008 Effect of egg position during three and 14 days of storage and turning frequency during subsequent incubation on hatchability of broiler hatching eggs. Poultry Science 87: 1237-1241 doi:10.33821/ps.2007-00469.

 

Eugene F 2004 A longitudinal analysis of chicken production systems of smallholder farmers in Leyte, Philippines. Leyte State University, Leyte, The Philippines.

 

Fayeye T R, Adeshiyan A B and Olugbami A A 2005 Egg traits, hatchability and early growth performance of the Fulani-ecotype chicken. Livestock Research for Rural Development. Volume 17, Art. #94. Retrieved April 21, 2011, from http://www.lrrd.org/lrrd17/8/faye17094.htm

 

Gueye E F 2003 Poverty alleviation, food security and the well-being of the human population through family poultry in low income food-deficit countries. Senegalese Institute of Agricultural research (ISRA), B.P.2057, Dakar-hann, Senegal.

 

Horst P 1988 Native fowl as a reservoir for genomes and major genes with direct and indirect effects on production adaptability. Proceedings of the 18th World Poultry Congress, Nagoya, Japan 4 – 9 September 1988, pp. 105. http://wildlife1.wildlifeinformation.org/S/00Ref/BooksContents/b41.htm, Last Accessed April 2011.

 

Illango J, Etoori A, Olupot H and Mabonga J 1999 Rural Poultry Production in two agro-ecological zones in Uganda, http://www.iaea.org/nafa/d3/public/12-rural-illango.pdf, Last accessed July 2010.

 

John A S and Merritt E S 1955 Heritability of albumen height and specific gravity of eggs from white Leghorns and Barred Rocks and the correlations of these traits with egg production. Poultry Science 34: 578-587.

 

Kabilika H S, Musonda M M and Sharma R N 1999 Bacterial flora from dead-in-shell chicken embryos in Zambia. Indian Journal of Veterinary Research 8: 1-6.

 

Khalafalla S W H 2000 Village poultry production in Sudan. Department of micro biology, Faculty of veterinary science, University of Khartoum, Khartoum, North Sudan, www.ipms-ethiopia.org/.../FinalThesis_MekonnenGebreEgziabher.pdf, Last accessed October 2009.

 

Kirunda H, Muwereza N, Kasaija D P, Kerfua D S and Jumanyol K 2010 Infectious and non-infectious factors affecting hatchability in indigenous chickens in Eastern Uganda. Africa Journal of Animal and Biomedical Sciences 5(3):51-59.

 

Kusina J F and Kusina N T 1999 Feasibility study of Agricultural and household activities as they relate to livestock production in Guruve district of Mashonaland Central province with emphasis on poultry production, HASP, Harare, Zimbabwe, pp. 129.

 

Kusina J F, Kusina N T and Mhlanga J 2000 Poultry production in Mashonaland Central Province: The role and opportunities for women. Integrated Crop-Livestock Production in Smallholder Farming Systems in Zimbabwe. Proceedings of a Review Workshop, Harare, Zimbabwe 10-13 January 2000, pp. 247-264.

 

Maphosa T, Kusina J, Kusina N T, Makuza S and Sibanda S 2004 A monitoring study comparing production of village chickens between communal (Nharira) and small-scale commercial (Lancashire) farming areas in Zimbabwe. Livestock Research for Rural Development. Vol. 16, Art. #48. Retrieved April 20, 2011, from http://www.lrrd.org/lrrd16/7/maph16048.htm

 

Minga U M,  Katule A,  Maeda T  and  Musasa J 1989  Potential and problems of the traditional chicken industry in Tanzania. In: proceedings of the 7th Tanzania Veterinary Association Scientific Conference, pp. 207-215.

 

Moges F, Mellesse A and Dessie T 2010 Assessment of village chicken production system and evaluation of the productive and reproductive performance of local chicken ecotype in Bure district, North west Ethiopia. African Journal of Agricultural Research, 5(13): 1739-1748.

 

Mwebaze N S 2006 Country pasture/forage resource profiles, Uganda, Special report of Ministry of Agriculture, Animal Industry and Fisheries, 2006. http://www.fao.org/ag/AGP/AGPC/doc/Counprof/Uganda.htm, Lased accessed February 2011.

 

Nemati M, Hermans K, Lipinska U, Denis O, Deplano A, Struelens M, Devriese L A, Pasmans F and Haesebrouck F 2008 Antimicrobial Resistance of Old and Recent Staphylococcus aureus Isolates from Poultry: First Detection of Livestock-Associated, Antimicrobial Agents and Chemotherapy 52(10): 3817–3819.

 

Nshemereirwe F 2004 Mushroom Cultivation in Uganda, Oyster Mushroom Cultivation, Mushroom Growers’ Handbook 1, Part III, Mushrooms Worldwide, Regional Research, Chapter 10, pp. 220.

 

Ojok L 1993 Disease as important factor affecting increased poultry production in Uganda. Tropical Landwirk 94: 7-44.

 

Olsen G H and Clubb S L 1997 Embryology, Incubation, and Hatching. In Avian Medicine and Surgery edited by R.B. Altman, S.L. Clubb, G.M. Dorrenstein & K. Quesenberry. WB Saunders Co, Philadelphia, USA, pp. 54-71 http://wildlife1.wildlifeinformation.org/S/00Ref/BooksContents/b12.htm, Last Accessed April 2011.

 

Parker J and Parker P 1969 The Practical Guide To Ornamental Waterfowl And Exotic Garden Birds. Arco, London.

 

PATH 2010 Monitoring ambient and cold chain temperatures during delivery of human papillomavirus vaccine in Vietnam and Uganda, Summary report September 2010, http://www.technet21.org/index.php/documentsview, p. 2

 

Ruiz J and Lunam CA 2002 Effect of pre-incubation storage conditions on hatchability, chick weight at hatch and hatching time in broiler breeders. British Poultry Science 43(3):374-83.

 

Sainsbury D 1992 Breeding and hatching. In Poultry Health and Management 3rd Edition, Blackwell Scientific Publications pp. 109-114.

 

Samli E H, Agma A and Senkoylu N 2005 Affects of Storage Time and Temperature on Egg Quality in Old Laying Hens. The Journal of Applied Poultry Research. 14: 548-558

 

Schmidt G S, Figueiredo E A P, Saatkamp M G and Bomm E R 2009 Effect of Storage Period and Egg Weight on Embryo Development and Incubation Results. Brazilian Journal of Poultry Science 11(1) 01-05.

 

Shahvali M, Moinizadeh H and Ardekani M A 2000 Local poultry management practices in southwest Iran, Indigenous Knowledge and Development Monitor 8(3): 8-12.

 

Siddiqui M A, Khan L A, Suradkar U S, Mendhe M S, Rindhe S N and Sirsat P R 2008 Bacterial isolation and their antibiogram in non-specific infections in poultry Marathwada region. Veterinary World 1 (2): 52-53.

 

Snedecor G W and Cochran W G 1989 Sample size determination, Statistical Methods. 8th Ed. Ames: Iowa State Press, In: Dell R B, Holleran S and Ramakrishnan R 2002 Sample size determination 43(4): 207-211.

 

Sola-Oja 2011 Evaluation of Reproductive Performance and Egg Quality traits in Progenies of Dominant Black Strain Crossed with Fulani Ecotype Chicken. Journal of Agricultural Science 3(1): 258-265.

 

Sonaiya E B and Swan S E J 2004 Incubation and Hatching, Small-Scale Poultry Production Technical Guide, Animal Production and Health, Food and Agriculture Organization of the United Nations, Rome, Chapter 5. http://www.fao.org/docrep/008/y5169e/y5169e06.htm, Last accessed April 2011.

 

Ssewannyana E, Ssali A, Kasadha T, Dhikusoka M, Kasoma M, Kalema J, Kwatotyo B A and Aziku L 2003 Characterisation of indigenous chickens in Uganda, In proceedings of the LSRP Annual Scientific Workshop, March 2003, Kampala.

 

Szwaczkowski T, Cywa-Benko K and Wezyk S 2003 A note on in breeding effect on productive and reproductive traits in laying hens. Animal Science Papers and Reports 21(2): 121-129.

 

Tadelle D and Ogle B 1996 A survey of village poultry production in the central highlands of Ethiopia. (M.Sc. Thesis) Swedish University of Agricultural Science, pp. 22. (www.fao.org/Ag/AGAInfo/resources/.../frg/.../tadelle.htm), Last accessed October 2009.

 

Tona K, Onagbesan O, De Ketelaere B, Decuypere E and Bruggeman V 2003 Effect of turning duration during incubation on corticosterone and thyroid hormone levels, gas pressures in air cell, chick quality and juvenile growth. Poultry Science 82: 1974-1979.

 

UBOS/ILRI 2002 Local poultry density in Uganda.

 

Walsh T J, Rizk R E and Brake J 1995 Effect of storage for 7 or 14 days at two temperatures in the presence or absence of carbon dioxide on albumen characteristics, weight loss and early embryonic mortality of broiler hatching eggs. Poultry Science 74:1403-1410.

 

Washburn K W 1990 Genetic variation in egg composition. In Poultry Breeding and Genetics Edited by R D Crawford, Elsevier Scientific Publishers, New York, pp. 781-798.

 

Weeks J 2003 Earth Sciences ID: 1064569035.Es, http://www.madsci.org/posts/archives/2003-10/1065121289.Es.r.html, Last Accessed April 2011.

 

Wilson H R 2004 Hatchability Problem Analysis, CIR1112, http://edis.ifas.ufl.edu, Last Accessed April 2011.

 

Wilson R T 1979 Studies on the livestock of Southern Sudan. Production of poultry under simulated traditional conditions. Tropical Animal Health Production 11: 143-150. 



Received 26 April 2011; Accepted 15 August 2011; Published 1 September 2011

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