I live in a area with some egg farms and I know the flocks are refreshed continuously and renewed en masse every two and a half to three years, with the farms always giving the option for locals to go there and buy as many chickens as they want.

Egg laying chickens are not very appreciated as meat birds as the animals have aged beyond the usual point regular meat birds are culled and the average person doesn't appreciate (nor knows how to prepare) the much more denser flesh.

One change I've been seeing is the move towards abandoning cages and adopting a bird on the soil system (also produces a good deal of almost ready to use manure, as the floor is constantly covered with sawdust or straw, which is sellable or can be used to produce methane) and more farms opting to move towards the free range approach, with the birds being allowed to move outside and graze.

It's a tentative move but it is a start.