Certainly, if it's just a matter of extra birds and they are healthy, culling can simply mean removing them from your flock, by giving them away or selling them. We've had several discussions on the board about the meaning of "cull". In days gone by, it always meant kill, but of late, when we say cull, it can mean kill or remove from your flock by other means.
If you raise chickens, putting one down may one day become necessary. In fact, I'd say it's inevitable and just a reality of owning a flock. Some birds cannot be sent to another person's flock for health reasons and therefore, must be euthanized humanely.