Ad hoc methods to control inbreeding include selecting a sufcient number of males, as the rate of inbreeding depends on effective population size; not overusing the males within the nucleus; restricting the number of close relatives selected, especially the number of males selected per family; limiting the number of females mated to each male; and avoiding mating between full and half sibs. These simple rules have been quite effective in maintaining a low level of inbreeding in commercial poultry and pig breeding.