Influence of the Cobb 500 hybrid parent age and egg storage period on incubation parameters

Main goal of this research was to determine the influence of Cobb 500 hybrid broiler parent age (BPA) and egg storage (ES) period, the impact of egg maturity on egg fertilization and chick hatching, as well as on embryonal mortality of chicks during incubation period. There were three phases of production cycle, three different ages of broiler parents 25, 41 and 58 weeks (BPA25, BPA41, BPA 58). The eggs there were differentiated according to storage time: eggs stored up to 7 days and eggs stored over 7 days (ES<7; ES>7). Using the random sample method, 1.050 eggs were chosen (total number of chosen eggs was 6.300), with the aim to determine above mentioned reproductive parameters, one day old chick weight and relative share of chick weight in total egg weight were determined. Age of broiler parents had the highest influence on egg fertility as the highest number of fertilized eggs was recorded during the middle of production cycle (BPA41 = 97.05%), then at the beginning of the cycle (BPA25 = 96.09%), and lowest number of fertilized eggs was during the last phase of the cycle (BPA58 = 93.00%). The storage period of the eggs did not have any influence on egg fertility. However, the age of broiler parents and storage period had significant influence on hatching, therefore it influenced embryonal mortality during incubation period. Without considering the storage period, the lowest embryo mortality was detected with eggs that originated from BPA41 – 13.05%, eggs that originated from BPA58 had significantly higher embryo mortality rate 15.87%, and the highest mortality rate was noted with eggs that originated from BPA25 16.93%. However, extended storage period for the eggs or egg maturity (ES<7 and ES>7) had influence on total embryonal mortality rate in all three phases of the production cycle. Moreover, broiler parent age had statistically significant influence on increase of egg weight (P<0.001) and hatched chick weight (P<0.001), while the relative share of chick weight in total egg weight was decreased, therefore storage period in all three phases of production cycle had negative influence on chick percent, with increase of storage time of the egg, relative share of chick weight in total egg weight decreased, especially during start BPA25 and end BPA58 phase of the production cycle (P<0.001).