Hatching Success of Ostrich Eggs Related to Axis of Setting, Turning Frequency, and Angle of Rotation.

Three trials were designed to study the effects of axis of setting, turning frequency and axis and angle of rotation on the hatching success of ostrich eggs. The joint effects of axis of setting and angle of rotation were investigated in a fourth trial. 2. The hatchability of fertile ostrich eggs artificially incubated in electronic incubators (turned through 60° hourly) was improved substantially in eggs set in horizontal positions for 2 or 3 weeks and vertically for the rest of he time. 3. The hatchability of fertile eggs set in the horizontal position without any turning was very low (27%). It was improved to approximately 60% by manual turning through 180° around the short axis and through 60° around the long axis at 08·00 and 16·00 h. A further improvement to approximately 80% was obtained in eggs automatically turned through 60° around the long axis in the incubator. Additional turning through 180° around the short axis twice daily at 08·00 and 16·00 h resulted in no further improvement. 4. The hatchability of fertile eggs set vertically in electronic incubators and rotated hourly through angles ranging from 60° to 90° around the short axis increased linearly over the range studied. The response amounted to 1·83% for an increase of 1° (R 2= 0·96). 5. The detrimental effect of rotation through the smaller angle of 60° around the short axis could be compensated for by setting ostrich eggs in the horizontal position for 2 weeks before putting them in the vertical position.