A word of warning first. I thought I would be able to kill my birds by 'wringing' their necks, I had read the books seen videos etc. I also tried breaking the neck of an oven ready chicken, and it was easy.
For various reasons, though, they were closer to 6 months than 6 weeks, and I failed laughably. I thought I had done the deed, and put the bird down, and instead of flapping it's last, it got up and walked nonchalently away . . . It could have been a lot worse, I could have injured it in the process. Though even if that had happened I had an alternative method ready, so it wouldn't have suffered for long. Cleaver, block and nail, and string.
When I prepared the bird for cooking I realised that there is a lot of difference between a 6 week old broiler, and a 6 month, free range bird! I could barely cut the neck, and nearly ended up using the cleaver again! There's no way I would have been able to break it's neck by hand, and I'm thoroughly glad I didn't try again.
I have nine birds too,
four of which are cockerles lol They are all currently quite happy together in a run 4ft x 16ft, despite some fighting when they had 3 or 4 times the space
The ideal system depends on how much space you have and a whole lot of other things, so is a very personal thing. Heck I don't even know what my own ideal system would be yet!
My biggest cockerel was still growing at a year old but I wouldn't dare try and kill him now
so I would say somewhere between day old and 18 months
Seriously, probably before 6 months, it depends how well you can cook, how much flavour you want and how big you want a bird to be for the table.
If you want to breed your own, yes go for a dual purpose breed, although several first generation crosses are highly recommended (not by me personally, I haven't got that far yet!)
As Vember says, better to make sure the new boy is fertile before getting rid of the old one. If nothing else, he'll make good stock and pies. :happy: