Effect of relative humidity during incubation at a set eggshell temperature

C. W. van der Pol*1, I. A. M. van Roovert-Reijrink1, C. M. Maatjens1, H. van den Brand2, R. Molenaar1 1

HatchTech B.V., P.O. Box 256, 3900 AG Veenendaal, The Netherlands. 2Adaptation Physiology Group, Wageningen University, P.O. Box 338, 6700 AH Wageningen, The Netherlands.

Hatching success in broiler chicken eggs is influenced by the amount of water loss from the egg during incubation (Davis et al., 1988; Buhr, 1995). In previous studies, water loss was often manipulated by changing the relative humidity (RH) inside the incubator while the machine temperature was maintained at a fixed setpoint. However, it is possible that the eggshell temperatures in these studies varied between RH treatments because the heat transfer capacity of air is different at a high or low RH.

Eggshell temperatures were not monitored or controlled. Changes in embryonic mortality found in previous studies to RH or water loss during incubation may have been a reflection of changes in eggshell temperature, rather than a result of the RH or water loss itself. By incubating eggs at the optimal eggshell temperature of 37.8ºC but with variable RH, effects on embryonic mortality, chick quality and development can be attributed to RH and water loss. Therefore, this study was performed to determine embryonic mortality, chick quality and postnatal development of chickens from eggs incubated at a high or low RH while maintaining the eggshell temperature at 37.8ºC throughout incubation. Download the entire article via the button below.