Bird incubation is a natural phenomenon that balances the needs of the parents for nourishment with the needs of the fetus for heat provision and protection . In this context, any means of communication between the fetus and the parents would have an adaptive value . The aim of the study was to investigate whether putative means of feto-maternal communication would correlate to physiological changes caused by environmental alterations. Oxygen consumption was used to measure fetal well being and six independent variables associated with fetal vocalizations and fetal movements were used to evaluate their potential for communicating the fetus statu quo. Broiler fetuses (Gallus gallus domesticus) of three developmental stages ( day 18, internally pipped and externally pipped) were challenged by a stepwise reduction in ambient temperature down to 30ºC. A linear drop in oxygen consumption in response to lowered temperatures was found in all three developmental stages indicating that the fetus was affected by the temperature changes. No differences correlating with temperature variations were found in any of the variables associated with fetal vocalization. Fetal vocalizations are consequently not used to communicate the thermal status of the fetus. Movement occurrence, movement intensity and ventilation frequency, however, followed a “maximum peak” trend, with a highest response at the third temperature interval (35.0-35.5 ºC). Considering that the lower limit of optimal development is between 35-36ºC, the results suggest that fetal movements can be of potential use to the incubating parent to assess the well-being of the fetus.

Keywords: Feto-maternal communication, prenatal, oxygen consumption, fetal vocalization, fetal movement, development.