There used to be a swap meet sort of thing at the Little Farmer's Market (go past the airport on 280 a mile or two and there is a building on the left with a red tin roof called the Little Farmer's Market. It is once per month- maybe the first Saturday of each month in the morning. I have been several times and there were always 10-15 backyard chicken raisers with chickens for sale, really nice people. Keep an eye out for it in the Iwanna, I haven't been in a few years, but they used to always advertise there. It may not start until summer.
There is a poultry auction in Waynesville every Saturday am (also listed in Iwanna), but the one time I went, I felt like the prices were high, but I might be out of touch with the market.
The Iwanna (Iwanna.com) is a good place to find chickens also.
Hope that helps! I am sure there is more, but that is all I know of.