Generally 'cull' means killing-for example, kangaroos in Australia are culled when there are so many that the alternative is for half the population to slowly starve to death, and deformed calves are culled from the herd shortly after birth.However, this is not always the case. When talking about chickens or any farm animals Culling is removing or getting rid of unwanted stock. It does not always mean killing the unwanted stock as you can c … ull a flock by selling off excess birds.