...To cull is not always to kill. wink
Cull simply means to remove from the genepool/flock. You can sell it, put it in another pen, give it away, or kill it.
This is pretty good. Cull is defined thus:
"cull"
verb (used with object)
1. to choose; select; pick.
2. to gather the choice things or parts from.
3. to collect; gather; pluck.
noun
4. act of culling.
5. something culled, especially something picked out and put aside as inferior.
Origin:
130050; Middle English coilen, cuilen, cullen < Anglo-French, Old French cuillir < Latin colligere to gather; see collect1
Culling has traditionally meant to kill the undesirable birds in a flock. There is a good reason for this.
Back when chickens weren't pets, but kept you and your family alive, it was important that undesirable traits like egg eating or deformities were kept out of the flock genetics.
Flocks were localized, and so new blood was most often a local thing, too... if it was available at all. The transport of live chicks from all corners of the nation, which we take for granted today, did not begin until the very early 20th century. Until then, the chickens in your valley were pretty much all you had to pick from.
Without culling for elimination, aka killing, a flock with "issues" could soon spoil the lot. No one cried about their "babies" when that happened - they went hungry.
So culling-as-killing was practiced to remove the possibility of bad genetics getting around and hurting everyone.