الفهرس 
Contents
Factors affecting embryonic growth and developmentOnly 14 pages are availabe for public view
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Abstract
This experiment was conducted on 1080 fertile eggs (62 grams average weight) collected from AL-SHROUK breeder farms of 34 weeks old breeding flock. These were checked for any breakage or abnormality and very small and very large eggs were rejected. After randomizing and numbering, eggs were kept in the egg trays and were disinfected by Viroxide super using foam device. The collected eggs were randomly divided into 3 groups of 360 eggs each according to storage periods (7, 14 and 21 days) and subdivide into 4 groups of 90 eggs each according to warming treatments (0, 4, 8 and 12 hours) on 99.5°F and 55%:60% RH, after the warming treatments eggs were placed for two hours in setter hall and back into cooler room at 16 – 18C and 60 – 80% relative humidity until to the end of all storage period. Results obtained could be summarized as follow:- 1. Storage period: * Eggs stored for 7 days recorded the best significantly values for number of fertile eggs, apparent fertility and hatchability percentage, hatchability for fertile eggs percentage, average chick weight and relative chick weights before storage. * Eggs stored for 21 days recorded the highest significantly number of un-hatched eggs and showed the highest number of total embryonic morality, weight losses and number of sticky chicks. * All storage periods didn’t show any significant effect on dirty eggs, pips (live or dead), abnormal chicks, average weight of eggs before and after storage, relative chick weights after storage and number of dead chicks. 2. Pre-heating treatments: * Control treatment (without preheating) showed highest percentages for chick weight related to egg weight before and after storage and highest values for average chick weight, weight loss. * Pre-hating for 4 hours showed the highest significantly values of hatchability and hatchability of fertile eggs. * Pre-hating for 12 hours showed the highest significantly number of un-hatched eggs and showed the highest number of total embryonic morality without any significant effect * Eggs weight after storage at the same storage period were significantly decreased with increasing pre-heating period. * Pre-hating treatment didn’t show any significantly effect on number of fertile eggs and apparent fertility %, dirty eggs, pips (live or dead), abnormal chicks, egg weights before storage, number of sticky and dead chicks. 3. Interactions among treatments: * Interaction between storage periods and pre-heating treatments showed significantly effect on apparent fertility and hatchability percentage, hatchability of fertile eggs, chick’s weight, un-hatched eggs, embryonic mortality, percentages for chick weight for egg weight ratio before and after storage sticky and dead chicks. * Interaction between storage periods and pre-heating treatments was not significant effect on number of fertile eggs, pips, abnormality, weight of eggs before storage, weight of eggs after storage and weight losses. Conclusions: Based on the obtained results, eggs can be stored until 7 days without any adverse effect on hatchability and the majority of incubation parameters; pre-heating for 4 hours reduces embryonic mortality and improves hatchability lead to increase storage period above 7 days till 21 days.