how many hens and cocks would you need to satisfy all your egg and meat requirements, and how do you select those to be eaten?
Three chickens is the minimum number for a succesful 'social' group, that woman recently who spent £1800 on her one chuck and couldn't understand why it was depressed should have done some research. (mind you I would probably get depressed having to live with someone so stupid they spent £1800 on a chicken).
Then its up to you. If you get 3 that are 'designed' to lay an egg a day then you should have plenty and lots to give away too. And it will let you play with adding things to their diet to get the most extraordinarily coloured yolks. But they have very little meat. Our first three, of this type, when
dispatched gave, between them, just enough meat for a coq-au-vin for 4 people.
And the egg laying ability of those varieties bred for eggs rapidly drops away after 12 months or so, as we are currently finding out with our second lot (15 months old and soon to head for the great hen-house in the sky)
If you go for modern meaty varieties, then they will be full sized and ready to eat before they reach egg-laying age. (and off course all males will be eaten as they are useless when it comes to eggs!, no further comments required here

).
Or you can pick a blended variety, some meat, some eggs.
As for choosing, well the males, off course and then after that, they all look the same to me.