That isn't the aim, at least consciously. I started off with naïve notions about preserving rare breeds, but I soon realized that rare breeds have tiny gene pools, some are probably rare for good reason, and they are relatively fragile health wise. Then I realized that rare breeds are usually creations of one person, and the SOP got crystalized/ fossilized at one (relatively recent in the grand scheme of things) time. That was a bit of a watershed moment. What is the point of preserving that? A chicken is an animal not a museum object, living in the world not a cabinet.
So now what motivates me is the notion that a mix of breeds developed in different places at different times from different mixes is most likely to supply the most diverse range of chicken genes here and now, and that those best suited to the environment will thrive, and those least suited will die out. I already had evolved and cold-hardy (Swedish) when I added selected and heat-tolerant (Penedesenca), and all breeds have been chosen as good foragers and predator-aware by repute. The Fayoumis just added should bring proven disease-resistance as well as a relatively ancient pedigree. So I'm trying to bring a large and diverse range of genes into the same pool and letting nature sort and select them. I don't think it's the same as selecting for lots of eggs or a hefty carcass for the table, but maybe it is...?