I'm glad you started this discussion, Luna. I've had chickens for about 9 years and have only ever culled for an ailment, not to eat.
My husband has been trying to talk me into meat birds for a couple years... This is how long it's taken me to try and wrap my head around it. My chickens are pets. All 93 of them. I never cared how old they were or if they were still laying, it didn't matter to me.
So after researching meat birds for a while I started thinking: Isn't it kind of silly to buy meat birds when I've got this many chickens? I wasn't really sure you could eat (read: chew) them if they were 5+ years. Apparently, you can. Silly me.
So, in this case, I've gone from pets only to the possibility of using the "dual" in "dual purpose".