Influence of age and body mass on the heating effect of microwave radiation in broilers

1. A total of 648 broilers was used in a factorial combination of 3 ages x 3 body masses x 4 microwave treatments to examine the possible interaction between bird age and body mass on the heating effect of microwaves. 2. As age or body mass increased, the increase in body temperature following exposure to microwaves decreased curvilinearly. 3. A significant interaction was evident between age and body mass. For the same body mass, microwave radiation exerted a greater heating influence at the younger age. 4. A model for the heating effect of microwaves is presented which takes into account the influence of both bird age and irradiated body mass.