It looks as if a lot of folks have mixed-breed flocks (I'm used to parrots, it's hard to think in terms of breeds rather than species, but I gather all domestic chickens are the same SUBspecies, let alone species) but Storrey's guide suggests that mixing breeds may lead to stress and problems. Has anyone found that to be they case? Storrey's also implies that adding younger chickens to a flock (i.e. when the older layers are no longer laying well) also causes stress and should be avoided. At this point, I'm looking at a flock of 3-4 hens who will be pets as well as layers (at this point, I'm not thinking in terms of "processing" them). If I really enjoy the experience, I can imagine doubling that, but if I retire my older hens, is it really a problem to add younger hens to the flock?