The effect of temperature on the hatching performance of ostrich chicks, and its implications for artificial incubation in forced draught wooden incubators

Abstract

Batches of 60-65 ostrich eggs were incubated in electronic incubators at 36.0, 36.5 and 37.3°C. The proportion of live chicks hatched relative to eggs set at 37.3°C (22/65 = 0.338) was impaired (p < 0.05) relative to those incubated at 36.0 and 36.5°C (respectively 38/60 = 0.633 and 36/60 = 0.600). Shell deaths were higher (p < 0.05) in fertile eggs incubated at 37.3°C than in those incubated at 36.0°C (28/50 = 0.560 vs. 14/52 = 0.269 respectively). Temperatures were recorded in three horizontal (front, middle and back) and three vertical (top, middle and bottom) positions in 10 forced draught wooden incubators. In general, a linear temperature gradient was found from the front to the back of these incubators. Temperatures recorded in the top tray of the incubators were higher (p < 0.05) than those recorded in the bottom and middle trays. Temperatures recorded in the front and back of the bottom tray were higher (p < 0.05) than those measured in corresponding positions of the middle tray. Mean temperatures of 37°C and higher were measured at the back of the top and bottom trays, as well as in the middle of the top tray. The hatching performance of ostrich chicks is likely to be impaired in these positions. It was assumed that younger embryos are less susceptible to excessive heat than older embryos. It was thus suggested that freshly laid eggs should routinely be placed in those positions where temperatures exceeded 37°C in forced draught wooden incubators.