4.4. Cooling rate

During the first day of life the cooling rate of chicks in different diet groups did not differ from each other (II, Fig. 2). On the seventh and eleventh day, chicks fed an insect-rich diet had a lower cooling rate than chicks fed a low-insect diet or a fish diet. Chicks fed a low-insect or a fish diet did not differ from each other. The response of wild chicks to cold was similar to that of chicks fed an insect-rich diet at the age of seven days. At the fifteenth day the cooling rate was similar in each diet group the first eight minutes, but the chicks fed an insect-rich diet could stay longer in the experiment. At the eighteenth day the cooling rate varied substantially, and differences among groups were not unambiguous. However, the chicks fed a fish diet seemed to cool faster than other chicks (II, Fig. 2). At the age of 21 days chicks fed an insect-rich diet could keep their body temperature relatively constant. The chicks fed a fish diet had significantly lower initial body temperature and they seemed to cool faster than other chicks.