Effect of the Date of Egg-laying on the Biological Value of Eggs and Reproductive Traits in Pheasants (Phasianus colchicus L.)

Pheasant eggs evaluated in the first period of egg-laying did not differ significantly in their weight and shape index and the values of both traits were, respectively, 30.7 to 32.2 g and 76.1 to 78.1%. Over the laying season the thickness of the shell decreased and its capacity for deformation and crush strength were greatest at the end of the laying season. The share of yolk in the egg was highest at the beginning of the laying season (35.3%), however over the peak of egg-laying and its final period the content of the albumen in the egg and the quality of eggs, expressed in Haugh units, increased. The best egg fertility and the results of chick hatch were observed from eggs collected at the beginning of the laying season (respectively, 92.5 and 81.6%) and about the fifth week of production (respectively, 94.4% and 73.9%). Chicks hatched from eggs collected at the early laying season were heaviest (21.5 g) and showed the highest share in egg weight (66.8%).