The aim of this study was to test some of the possible means of feto-maternal communication correlated with decreasing temperatures. Fetuses of three developmental stages were exposed to five temperature intervals (40-30◦C)

The first step of the study was to look at what effects, if any, the temperature variations had on the fetuses. To do so measured oxygen consumption and ventilation frequency. Oxygen consumption is strongly correlated with the temperature of the living fetus. If the levels of oxygen consumption decreased it is an indication that the environment for the fetus is changing and consequently the fetus is exposed to a stressful situation.

The breathing frequency can only be measured after internal pipping but can than be used as an indication that some kind of activity occurs that leads to a higher or lower breathing frequency.

From the results we could see that the levels of oxygen consumption, decreased linearly with decreasing temperatures. Therefore we knew that the decreasing temperatures in the experiment had physiological effects on the fetus. The effect decreasing temperatures had on the breathing frequency was however different. The results showed an occurrence of a maximum peak that occurred during at the third temperature interval (35.0-35.5 ºC).  

Now when we know that the fetus is affected by the temperature changes we want to look at possible means the fetus have to communicate this physiological changes to the incubating parents. In what ways can the fetus inform the parent that the incubation environment is no longer beneficial for proper development? The means we decided to look at where variables of fetal-vocalization and fetal-movement.

All variables where now measured while the eggs where exposed to the five level temperature treatment. After analyzing the data we got the following results:

Fetal-vocalization is not used to communicate low incubation temperatures in chicken fetuses during the last days of incubation. The only relationship found in the study was that fetuses seem to vocalize more intensely closer to hatching, but still with no correlation to temperature.

Fetal-movement can be use to communicate low incubation temperatures in chicken fetuses during the last days of incubation. Several fetal-movement variables showed the same maximum peak during the third interval as seen in breathing frequency.

The temperature during the third interval (35.0-35.5 ºC) is the same as the reported value of lower limit of optimal development (36.0^◦C) which leads me to conclude that there is a behavioural response which is triggered by a specific temperature threshold associated with lower limit of optimal development.

Further studies will reveal if this response can be detected by the incubating parent and consequently is a mean on feto-maternal communication.