Well, yes, I agree with Fowlafoot. Commercial production strains are efficient and cost effective, but they're rapidly becoming a huge, static genetic pool. When I say this, I'm referring primarily to the big-time industrial breeds like the production White Leghorn. I'm not referring to hatchery-based consumer-marketed production birds like the Comet. What bigzio meant rather than "healthier" may have been "more natural." Heritage breeds are sometimes resistant to diseases that could wipe out the genetically similar commercial layers, and they maintain natural abilities such as broodiness that we have artificially bred out of most of the hatchery production strains.
Sure, breeds like the Delaware were inbred in the past, but there are now folks interested in breed preservation that have been working with these breeds to recoup them from obscurity and make them healthier. Not to mention the fact that hatchery strains of heritage birds are some of the healthiest birds you'll see, because they've been outcrossed for vigor and production. They may not make the show circuit, and might disappoint the history/heritage buff, but darned if they're not healthy.
With the new interest in homesteading, self-sufficiency, and locally-produced food, there's a lot of renewed interest in the old heritage breeds that make good all-around family farm birds. This is very good news for rare breeds like the Delaware and the Buckeye, which excel at being old-timey dual-purpose chickens.