goldenyears
Songster
Very Frank Herbert of you!Yes. Lower your expectations. Now lower them some more. Disappointed yet? Lower them even further.
Modern birds have been bred to be larger, lay more frequently, and often grow faster than their counterparts of even a hundred years ago. The consequences of all that breeding is that they are far more dependent upon us, and far more dependent upon a nutritionally complete modern feed/diet to perform.
Ancient breeds - jungle fowl - aren't particularly well suited to your climate, but free range extremely well (in their native conditions). They are also tough, not particularly meaty, lay only rarely, and not large eggs at that. Oh yeah, and free ranging means that they are likely to lay eggs all kinds of places you won't find them.
I'm in Fl, USDA Growing zone 8a - while occasionally hotter, I have a longer growing season than you do, a milder winter, and average 1" of rain+ weekly. I'm also on flatter ground than you likely enjoy in NC. You can see my efforts to create a free ranging birds suitable for local conditions, here. and you can see (incomplete) my efforts to bend my feed curve with a biodiverse polyculture, here. Tl;dr - a year of non-stop breeding and frequent culling has provided a couple misses which qualify as forward progress, and one hopefull. I should be pretty close to "there" in four to six years, at the current rate. ...and free ranging saves me 15-35% (seasonally dependant) on my feed costs, but also means that, at any given weight, my birds are more flavorful, have more chew, and took longer to arrive at weight than a similar bird raised in more conventional (coop and run, free feeding) conditions.
I have SLW. They are predator aware, a bit flighty, better free rangers than some of my others. I like them - smart birds. They also take 7 months to maturity, lay eggs maybe three days out of five, and the eggs are medium, sometimes medium-large, almost never large. Bigger than my purpose-built Comets (an RSL-type), the hens still only weigh 4.5-5# and took half a year to get there. SLW, BTW, were bred roughly 100+ years ago as an improvement upon the dual purpose breed, Brahma - which are (eventually) big birds, buit does it ever take forever for them to get there - and they lay no better than SLW, either.
People are breeding "Ranger" lines for improved meat on carcass, decent free ranging ability, and faster growth - but the very impressive numbers coming out of the best of those lines are still coming from very traditional management practices - not turning them loose, offering some feed, and engaging in magic ritual with hopes of success. "Fingers Crossed" is rarely a successful strategy, and never reliable, year over year. Neither is "hope and prayer", "a wing and a prayer", "blood for the blood god", or any other similar practice.
Modern birds were bred on the altar of technology. If you want them to perform at anything like their potential, you need to continue to sacrifice upon the altar of technology. If, instead, you wish to return to ancient roots, and ancient levels of performance - start a culling project, and prepare yourself for Bene Gesserit levels of patience in the creation of your Kwisatz Haderach.