INFLUENCE OF AGE ON PHYSICAL TRAITS OF JAPANESE-QUAIL (COTURNIX-COTURNIX-JAPONICA) EGGS

External and internal traits of Japanese quail eggs during 6 months of lay were analyzed. Variables such as egg weight, specific gravity, eg g shape index, albumen and yolk heights and their indices, internal qu ality unit (IQU) and shell and membrane thickness were recorded at 8, 12, 17, 21, 25, 30, 34 and 39 weeks of age. Egg weight, egg length, yo lk height and yolk index increased as quail aged. Specific gravity, sh ell plus membrane thickness, egg shape index, albumen height and IQU d ecreased at the end of the experiment. Highest values of shell thickne ss (0.201 mm) and IQU (69.68) obtained at 17 and 8 weeks of age, respe ctively, indicated that a better quality of egg was attained at the be ginning of lay.