EN
The kind and degree of injuries in dead embryos coming from hens Astra В in case of low values of cooling have been described. Seasonal hyperheatings of embryos due to hypoventilation brought about the lowered indices of chat- ching and the worse quality of chickens. It was shown that hyperthermy of embryos in a breed chamber led to some distrurbances in the system of circulation. There were observed extravasations of blood from allantoic vessels and injuries of the umbilical vessel, defects of cardiac cells, and distention of cardiac chambers. It was found that an increased number of cases with the badly healed navel in chickens was not always related with the environment of a breed chamber; it might also occur earlier uder the influence of disturbed microclimate in a chatching chamber.