Effects of Sibling Eggs Contact on Incubation Length and Hatching Synchrony in Red-Legged Partridge (Alectoris rufa)

Hatching synchrony is a desirable trait in the artificial incubation of eggs because it permits the simultaneous extraction of all the chicks from the hatcher, thus minimizing extraction queues. This study aimed at evaluating the effects on egg performance, incubation length, and hatching synchrony of different sibling contact regimes during the incubation in red-legged partridge (Alectoris rufa) eggs. To achieve these objectives, 196 eggs were arranged in four treatments according to the sibling eggs contact regime: (a) eggs without contact during the whole incubation process; (b) eggs in contact during the incubation phase (from day 1 to 20 of incubation); (c) eggs in contact during the hatching phase (from day 20 of incubation to hatching); (d) eggs in permanent contact throughout the incubation process (from day 1 of incubation to hatching). Development stage at embryonic mortality, hatchability, and egg weight loss during incubation were not affected, but incubation length was shortened and hatching synchrony was increased in eggs in contact during the hatching phase. The main conclusion was that keeping red-legged partridge eggs in close contact during the hatching stage in the artificial incubation does not affect hatchability but allows hatching synchrony to be maximized, facilitating the handling of 1 day old chicks.