Start with your Extension office. Just say you want to do a pastured poultry operation. They probably have a pamphlet ready for you since it has become more and more popular since the Joel Salatin books came out. Generally, it's not too bad to figure out the system. The only 'issue' is that poultry is not USDA inspected (except for processors who do over 19,999 birds per year) so every state will have its own quirks.
In our state, they simply require you to use a processor (outside of one permit which allows you to do it yourself from home, but you have to slaughter,dress and sell the birds within 48 hours from your own home... not really practical for crops of 50). It's simply to protect human health. I don't see that as being 'red tape' as much as common sense. It does add around $1/lb to your cost, though. Include your gas to and from the processor in your pricing (depending how far you go, it's a rather shocking bump up in your price per pound).
Oh, and I mean this. Get a business license and insurance. It's very inexpensive step to take and protects your personal property in case of something bad happening. It also allows you to deduct your operating expenses. Let me know how your business plan works out. I've never thought of marketing them live at auctions. I really love raising our own meant birds because the quality can't be beat. But I'm not lying when I say I make more profit selling 2 dozen eggs than I do from an entire meat chicken. It's a labor of love... and in my mind a good way to get our customers eating healthy and moving up to the lamb, pork and beef where we have a larger profit margin.