How old are your meat chicken/roos when you, ehm, harvest them?

We're going to get a bunch of meat chickens this year, either as fertilized eggs to hatch or as (very) young birds.
I'd like to know; how old are your meat birds (chicken) when you harvest them?

Thank you in advance!

I've done 3 batches now, all were killed at 8-10 weeks, just based on when it was convenient.

That's about right - they put on weight really quickly.  If you need to "sex" them - look carefully at the legs of the chicks.  The males always have sturdier legs.  Just a thought - not helpful if they are all the same sex!  

I prefer them before they start crowing, or just as they begin;  in my experience, they get tougher and stringier--not meatier--after this point.  Usually between 8-12 weeks, depending on breed.  We had some Australorps that we got tired of waiting for them to crow and killed them at about 6 months;  they were still lovely and tender.  

We haven't had any meat birds/cockerels for several years now but we very rarely buy supermarket chicken as it just doesn't compare with home raised.

Thank you!
Chicken is my favourite kind of meat (turkey too - oh, and duck! haha) and we usually buy from the supermarket because all our chicken have names and our hearts are just too soft. But we want to become more self sustaining, not only because of the economics of it but also for knowing where our food comes from and how it was grown - plus taste and nourishment value!
Store-bought is often "empty", home grown so much more satisfying :)