عنوان مقاله [English]
The aim of this study was to determine the causes of fertile eggs rejection in the hatchery of Namin City, located in northeastern part of Ardabil province, Iran, from March 2016 to September 2016. The data were collected by frequent reference to the hatchery and the total of fertile eggs and hatched eggs from broiler breeder flocks with different ages was recorded; moreover, unhatched eggs were thoroughly investigated. In this period, 2402605 fertile eggs were examined, out of which 2372604 eggs were hatched, whereas 30001 eggs (1.248 %) were unhatched and discarded for abnormalities. The lowest and the highest average percentage of fertile eggs rejection concerned those 28 and 32 weeks old and those older than 52 weeks, respectively. September had the highest average percentage of discarded eggs. Twelve types of abnormality were identified for the discarded eggs. The abnormalities include cracked shells (32.03%), malformed shells (21.02%), very large size eggs (13.04%), broken shells (11.56%), very small eggs (6.50%), dirty shells (5.47%), thin shells (3.46%), bloody shells (2.55%), cuticle-free shells (1.74%), wrinkled (corrugated) shells (1.39%), calcium splash (chalky deposit) (0.78%) and color change in shells (0.39%). According to the results of this study, cracked shells and malformed shells constituted the most common abnormalities (53.05% and 0.661%, respectively) out of the total condemned eggs and fertile eggs. The results of this study showed that age of flocks and heat stress were the most significant causes of egg abnormalities.
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