I have actually been thinking about this too. We have 12, 1yr olds and I know they will stop laying eventually. We had our last hen until she was close to 7 yrs. She would pop out an egg every couple weeks. I have actually started designing a "retirement" coop so I will be able to move out the non-layers and replace them. The new coop will only have 1 nesting box for the occasional layer. Although all of mine are not pets with names, I don't think I could kill them.