Sensitivity to odours in the embryo of the domestic fowl.

Sensitivity to odours in the embryo of the domestic fowl was investigated on the day before hatching. Embryos were tested with four odorants: dichloroethane, cineole, amyl acetate and formic acid. Three odorants (dichloroethane, formic acid and cineole) produced an increase in the heart rate and a rise in the rates of beak-clapping and the first two increased the amount of head-shaking. Odorants had little effect on other types of activity. The response to amyl acetate varied between experiments. Blocking the nostrils with wax abolished the response. Some implications of these results are discussed briefly.