Effects of external stimulation on the onset of lung ventilation and the time of hatching in the fowl,duck and goose

Effects of naturally occurring and artificial stimulation on foetal development and the time of hatching were investigated in the fowl, duck and goose.

With respect to natural stimulation, it was shown in the fowl, that the time of hatching is advanced by contact with an egg given 24 h more incubation. Also in the fowl, it was found that contact with other eggs given the same amount of incubation reduces the spread of hatching, although without affecting the mean hatching time. In the Khaki Campbell duck, however, eggs kept in contact hatched earlier than isolates, as well as hatching within a shorter period of time.

The artificial stimulation used was that known to have an accelerating effect in the quail, and the developmental stage of the foetus was assessed by recording pressure changes within the air space of the egg, a method which reveals the time of onset of lung ventilation. When eggs were stimulated artificially it was found in the fowl, duck and goose that the stimulated eggs not only hatched earlier, but began to breathe earlier than did their unstimulated controls. In all three species also, the duration of breathing was shorter in the stimulated than in the unstimulated foetuses.