The experiment was carried out with Muscovy ducks to study the influence of age and laying time on their egg quality. In addition the relationship between egg water loss during storage, shell thickness and storage time were tested. a total of 2920 eggs were collected and individually weighed, washed, fumigated and stored for a maximum period of 7 days. Then the eggs were incubated and candled on the 10th day. All the shell obtained from unfertile eggs (10th day), died embryo eggs (10th and 30th day) and hatched eggs (34th day), were immediately cleaned by washing and dried in a forced draught stove. Individual egg measurements included: egg weight at collection and at incubation, shell weight and shell thickness. Shell weight per unit of egg surface area (SWUSA), water loss per unit of time, avg. shell thickness and percentage of shell on egg weight were calculated. Results obtained in this study show that the duck egg stored at 11+-0.2°C and R.H. 70-75% loose 0.03 g of water for each day of storage (P<0.001). Hatching rate is affected (P<0.05) by water loss during storage period and the best results (70.34%) are obtained when water loss per week is about 1% of egg weight. Shell thickness, weight, percentage of shell on egg weight and SWUSA are significantly affected by laying time and age of bird (P<0.01). these parameters tend to decrease with the passing of laying -period and age of bird. A relationship between hatching outcome and shell weight percentage of shell on egg weight and SWUSA was observed (P<0.01). Moreover results showed that although shell weight increases with increasing egg weight (b=+0.82), it does not do so proportionally, consequently there is concomitant decrease in percentage of shell on egg weight (b= -0.028).
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