Quality of Eggs and Hatching Traits in Two Slow-Growing Dual-Purpose Chicken Lines Reared Conventionally or on Pasture

The quality of eggs and the hatching traits of two slow-growing lines – La Belle (LB) and Bresse Gauloise (BB) reared under conventional or alternative system with pasture access were compared. The birds of both lines in the study were at the age of 27-37 weeks. Two-way ANOVA was used to assess the effect of the rearing system as well as the line on the quality characteristics of the eggs and hatching traits of the LB and BB lines. Both factors affected to a different extent the examined traits. The effect of the rearing system was much stronger than that of the line in regard to the quality of the eggs. The birds reared on pasture had increased weight (P<0.001) of the eggs and its components-yolk, albumen and shell (P<0.001), however the alternative system decreased significantly the colour (P<0.001) of the yolk. The influence of the line was more pronounced in terms of the hatching traits, however it often interacted with the rearing system. Generally, the fertility of the eggs of the BB line dramatically decreased when reared conventionally (P<0.001), as did their hatchability when expressed as percentage of the total number of the eggs (P<0.001). On the other hand, the hatchability of the fertilized eggs was positively affected by the alternative system (P<0.001) and higher in the BB linе displaying their higher adaptability in comparison with the LB line.