some people do raise heritage breeds for meat. and they do get some money off of them. but those are in niche markets. some gourmet shefs only use heritage breeds of animals, because they typically have a better flavor to them, compared to cornish cross, precisely because they grow slower, finishing out in 24 weeks or so. It is an option, but you have to be sure you have a market for it first. Otherwise, you'll have alot of pretty pets.