I'll just throw this out there for the OP as food for thought...
Is the rural market your best option? I don't know how close you live to more populated towns/cities, but I would think that they would provide a much stronger market than rural would. A lot of my relatives farm, and if they wanted chickens, they'd just build something themselves. Much like
@jthornton said, it'd be with materials that they had on hand.
I think something to consider - take all the advice you're being given here, come up with some solid plans based on sizes that would work well for areas in town or cities (say a flock of 4-6, 6-8, etc), then, build a prototype or two, and get the system down. Then, make it self-assemble. By that, I mean, cut the pieces to fit, include the fasteners to put everything together, and offer two options - they buy it flat, and assemble themselves, or for a charge, you'll assemble. With a quality "kit" that's ready to be assembled, I think you could pull in the people that are handy enough to assemble, but don't have the space/time/knowledge to do a full on build. Those that want it all and just have it delivered, you can provide that as well.
I think if you went with quality, ready-to-assemble, and targeted the more populated areas that don't have the means to easily build themselves, you could give yourself the best shot to make it work. Granted, you need to be within reasonable distance of some more populated areas. To me, rural folks are more used to finding their own solutions and may not be so quick to lay out money for something they can try to manage themselves. Folks in town may romance the idea of doing it themselves, but the practicality factor would make them more likely to buy a quality product, and do the last 10-15% assembly themselves.
Anyway, just something to mull over.