Effect of egg weight categories, storage time and storage temperature on incubation lenght in duck eggs (Cairina moschata L. and anas platyrhyncos domestica L.)

The effect of storage time (3,7 and 14 days), storage temperature (18±1°C and 15±1°C) and egg size (average weight -2*std.dev., -1* std.dev., +1*std.dev., and +2* std.dev.) on the incubation length of Muscovy and Pekin duck eggs was studied. Incubation was carried out in a commercial multi-stage incubator and the eggs were daily sprayed from the 10th to the day of egg transfer. Pekin duck results showed that storage from 3, through 7, to 14 days, significantly prolonged the incubation time either at 15°C or 18°C (15°C: 27.92, 28.11 and 28.31 days; 18°C: 27.89, 28.08 and 28.25 days; Hatch-time= 27.82+0.0343 storage). Similarly, egg size influenced the incubation time (27.89, 28.02, 28.11, 28.18 days, for 72.2 g <>77.4 g, 77.5 g<>82.8 g, 82.9 g <>88.1 g and 88.2<>93.5 g, respectively). Muscovy duck results showed that storage prolonged the incubation time: at 18°C, 33.74, 34.18 and 34.60 days, for 3, 7 and 14 days of storage, respectively; at 15°C, 35.20 and 33.91-34.00 for 14 days and 3-7 days, respectively, (P<0.05) Hatch-time=33.48+0.097 storage. Egg size influenced the incubation time but significant differences (p<0.05) were observed only between the lighter eggs (70.4-76.2 g) compared to all the other categories: 4h and 35’ less than in the reference category (76.3 g – 82.1 g). Since optimum hatchability and duckling quality can only be achieved when chicks hatch contemporaneously, in commercial duck hatcheries the correction for the storage length and for lighter eggs in Muscovies and lighter and heavier eggs in Pekins is strongly advised.