Effect of Egg Weight on Hatchability and Subsequent Performance of Potchefstroom Koekoek Chicks

A study was conducted to determine the effect of Potchefstroom Koekoek chicken egg weight on hatchability and subsequent chick performance. In the first part of the study, a total of 450 Potchefstroom Koekoek eggs were used in a complete randomized design to determine the effect of egg weight on hatchability, embryonic deaths, egg weight loss and hatch weight. The eggs were allocated into three weight-treatments: large (>55 g, A), medium (45-55 g, B) and small (<45 g, C). Hatching yield, hatchability, embryonic deaths, egg weight loss and hatch weight were significantly (p<0.05) affected by the weight of the eggs. The large and medium-sized eggs had higher hatching yield (60 and 70%, respectively). The medium-sized eggs had higher (p<0.05) hatchability values than both small and large-sized eggs. Medium-sized eggs had lower (p<0.05) embryonic. deaths (31%) than small (45%) and large (36%) egg sizes. The large-sized eggs had higher hatch-weights than small and medium-sized eggs. The total embryonic deaths, hatching yield and hatchability percentages were optimized within the medium-sized eggs (51 g, r(2) = 100). The second part of the study was aimed at determining the effect of Potchefstroom Koekoek egg weights on subsequent chick performance and carcass characteristics. The chicks were fed a growers diet containing 11.97 ME MJ kg(-1) DM feed of energy and 161 g kg(-1) CP. Feed and water were given ad libitum. All the performance parameters were significantly (p>0.05) influenced by egg weight except mortality of the chicks at both starter and finisher phases. The large-sized egg had high (p<0.05) weight gain, better (p<0.05) daily feed intake (36 and 94 g) and feed conversion ratio (3.0 and 5.1) for both starter and finisher phases, respectively. It can be concluded that for better hatchability medium-sized eggs can be considered. However, if growth performance is of primary importance large-sized eggs can be used.