ANALYSIS OF THE BROODING CYCLE OF BROODY JUNGLEFOWL HENS WITH CHICKS

Broody hens with chicks show a sequence of behaviors that is cyclical in nature: brooding, preening, feeding with drinking, exploring, dustb athing, and then brooding once again. In inexperienced hens, the avera ge cycle length was about half an hour, with brooding and feeding taki ng up about 90% of the time. The amount of brooding, preening, and fee ding correlated positively with the length of the cycle, whereas explo ring and dustbathing had no significant effect on cycle length. Hens w ith previous experience brooding chicks showed a significantly shorter cycle length, but the sequence of behaviors was unaltered. The result s were discussed in the context of ultradian rhythms in behavior. A cl ock mechanism was not able to account for the results. A model that in cluded the interaction of causal factors provided by the chicks and by the hen's dustbathing system was more successful.