I've been wondering about this myself. We are not to that point yet, our oldest chickens are 1 year old. Ours are not pets, we have not (and do not plan on) naming them. We are raising the hens primarily for the eggs, so I don't know that I would want to keep paying to feed hens that are past laying, unless I've got a special relationship with one.
We do plan on raising meat birds next year, but I've already wondered about what to do with the laying hens as they age. I'm still thinking on this one, just as I am torn about processing our own meaties vs. paying someone else to do it. My husband has told me if I want to process them myself he has no intention of helping, but he is a big softy and was raised in a farming family like I was.
So my answer is; I have no idea yet and hopefully don't have to worry about that for a few years, until after I've had more experience with chickens in general.